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postgresql/src/test/isolation/expected/classroom-scheduling.out

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Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Parsed test spec with 2 sessions
starting permutation: rx1 wy1 c1 ry2 wx2 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
1
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: rx1 wy1 ry2 c1 wx2 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c1: COMMIT;
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: rx1 wy1 ry2 wx2 c1 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c1: COMMIT;
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: rx1 wy1 ry2 wx2 c2 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: rx1 ry2 wy1 c1 wx2 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: rx1 ry2 wy1 wx2 c1 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c1: COMMIT;
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: rx1 ry2 wy1 wx2 c2 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: rx1 ry2 wx2 wy1 c1 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: rx1 ry2 wx2 wy1 c2 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c2: COMMIT;
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: rx1 ry2 wx2 c2 wy1 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: ry2 rx1 wy1 c1 wx2 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: ry2 rx1 wy1 wx2 c1 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c1: COMMIT;
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: ry2 rx1 wy1 wx2 c2 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: ry2 rx1 wx2 wy1 c1 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: ry2 rx1 wx2 wy1 c2 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c2: COMMIT;
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: ry2 rx1 wx2 c2 wy1 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: ry2 wx2 rx1 wy1 c1 c2
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;
step c2: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: ry2 wx2 rx1 wy1 c2 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c2: COMMIT;
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
starting permutation: ry2 wx2 rx1 c2 wy1 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c2: COMMIT;
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
ERROR: could not serialize access due to read/write dependencies among transactions
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step c1: COMMIT;
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
starting permutation: ry2 wx2 c2 rx1 wy1 c1
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step ry2: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:30';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
0
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wx2: UPDATE room_reservation SET start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 13:30', end_time = TIMESTAMP WITH TIME ZONE '2010-04-01 14:30' WHERE room_id = '101' AND start_time = TIMESTAMP WITH TIME ZONE '2010-04-01 10:00';
step c2: COMMIT;
step rx1: SELECT count(*) FROM room_reservation WHERE room_id = '101' AND start_time < TIMESTAMP WITH TIME ZONE '2010-04-01 14:00' AND end_time > TIMESTAMP WITH TIME ZONE '2010-04-01 13:00';
Improve display of query results in isolation tests. Previously, isolationtester displayed SQL query results using some ad-hoc code that clearly hadn't had much effort expended on it. Field values longer than 14 characters weren't separated from the next field, and usually caused misalignment of the columns too. Also there was no visual separation of a query's result from subsequent isolationtester output. This made test result files confusing and hard to read. To improve matters, let's use libpq's PQprint() function. Although that's long since unused by psql, it's still plenty good enough for the purpose here. Like 741d7f104, back-patch to all supported branches, so that this isn't a stumbling block for back-patching isolation test changes. Discussion: https://postgr.es/m/582362.1623798221@sss.pgh.pa.us
2021-06-23 17:12:31 +02:00
count
-----
1
(1 row)
Implement genuine serializable isolation level. Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen
2011-02-07 22:46:51 +01:00
Strip whitespace from SQL blocks in the isolation test suite. This is purely cosmetic, it removes a lot of IMHO ugly whitespace from the expected output.
2011-08-18 11:16:10 +02:00
step wy1: INSERT INTO room_reservation VALUES ('101', TIMESTAMP WITH TIME ZONE '2010-04-01 13:00', TIMESTAMP WITH TIME ZONE '2010-04-01 14:00', 'Carol');
step c1: COMMIT;