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postgresql/src/include/access/heapam.h

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Somehow the 'comment' here got messed up
1998-01-25 06:04:21 +01:00
/*-------------------------------------------------------------------------
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
*
Change my-function-name-- to my_function_name, and optimizer renames.
1999-02-14 00:22:53 +01:00
* heapam.h
Massive commit to run PGINDENT on all *.c and *.h files.
1997-09-07 07:04:48 +02:00
* POSTGRES heap access method definitions.
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
*
*
Update copyright for 2014 Update all files in head, and files COPYRIGHT and legal.sgml in all back branches.
2014-01-07 22:05:30 +01:00
* Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
Add: * Portions Copyright (c) 1996-2000, PostgreSQL, Inc to all files copyright Regents of Berkeley. Man, that's a lot of files.
2000-01-26 06:58:53 +01:00
* Portions Copyright (c) 1994, Regents of the University of California
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
*
Remove cvs keywords from all files.
2010-09-20 22:08:53 +02:00
* src/include/access/heapam.h
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
*
*-------------------------------------------------------------------------
*/
Massive commit to run PGINDENT on all *.c and *.h files.
1997-09-07 07:04:48 +02:00
#ifndef HEAPAM_H
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
#define HEAPAM_H
Restructure indexscan API (index_beginscan, index_getnext) per yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
2002-05-21 01:51:44 +02:00
#include "access/sdir.h"
Improve our #include situation by moving pointer types away from the corresponding struct definitions. This allows other headers to avoid including certain highly-loaded headers such as rel.h and relscan.h, instead using just relcache.h, heapam.h or genam.h, which are more lightweight and thus cause less unnecessary dependencies.
2008-06-19 02:46:06 +02:00
#include "access/skey.h"
Clean up the #include mess a little. walsender.h should depend on xlog.h, not vice versa. (Actually, the inclusion was circular until a couple hours ago, which was even sillier; but Bruce broke it in the expedient rather than logically correct direction.) Because of that poor decision, plus blind application of pgrminclude, we had a situation where half the system was depending on xlog.h to include such unrelated stuff as array.h and guc.h. Clean up the header inclusion, and manually revert a lot of what pgrminclude had done so things build again. This episode reinforces my feeling that pgrminclude should not be run without adult supervision. Inclusion changes in header files in particular need to be reviewed with great care. More generally, it'd be good if we had a clearer notion of module layering to dictate which headers can sanely include which others ... but that's a big task for another day.
2011-09-04 07:13:16 +02:00
#include "nodes/primnodes.h"
Split tuple struct defs from htup.h to htup_details.h This reduces unnecessary exposure of other headers through htup.h, which is very widely included by many files. I have chosen to move the function prototypes to the new file as well, because that means htup.h no longer needs to include tupdesc.h. In itself this doesn't have much effect in indirect inclusion of tupdesc.h throughout the tree, because it's also required by execnodes.h; but it's something to explore in the future, and it seemed best to do the htup.h change now while I'm busy with it.
2012-08-30 22:15:44 +02:00
#include "storage/bufpage.h"
Clean up the #include mess a little. walsender.h should depend on xlog.h, not vice versa. (Actually, the inclusion was circular until a couple hours ago, which was even sillier; but Bruce broke it in the expedient rather than logically correct direction.) Because of that poor decision, plus blind application of pgrminclude, we had a situation where half the system was depending on xlog.h to include such unrelated stuff as array.h and guc.h. Clean up the header inclusion, and manually revert a lot of what pgrminclude had done so things build again. This episode reinforces my feeling that pgrminclude should not be run without adult supervision. Inclusion changes in header files in particular need to be reviewed with great care. More generally, it'd be good if we had a clearer notion of module layering to dictate which headers can sanely include which others ... but that's a big task for another day.
2011-09-04 07:13:16 +02:00
#include "storage/lock.h"
Improve our #include situation by moving pointer types away from the corresponding struct definitions. This allows other headers to avoid including certain highly-loaded headers such as rel.h and relscan.h, instead using just relcache.h, heapam.h or genam.h, which are more lightweight and thus cause less unnecessary dependencies.
2008-06-19 02:46:06 +02:00
#include "utils/relcache.h"
Move the HTSU_Result enum definition into snapshot.h, to avoid including tqual.h into heapam.h. This makes all inclusion of tqual.h explicit. I also sorted alphabetically the includes on some source files.
2008-03-26 22:10:39 +01:00
#include "utils/snapshot.h"
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
Improve bulk-insert performance by keeping the current target buffer pinned (but not locked, as that would risk deadlocks). Also, make it work in a small ring of buffers to avoid having bulk inserts trash the whole buffer arena. Robert Haas, after an idea of Simon Riggs'.
2008-11-06 21:51:15 +01:00
/* "options" flag bits for heap_insert */
#define HEAP_INSERT_SKIP_WAL 0x0001
#define HEAP_INSERT_SKIP_FSM 0x0002
Reduce scope of changes for COPY FREEZE. Allow support only for freezing tuples by explicit command. Previous coding mistakenly extended slightly beyond what was agreed as correct on -hackers. So essentially a partial revoke of earlier work, leaving just the COPY FREEZE command.
2012-12-02 21:52:52 +01:00
#define HEAP_INSERT_FROZEN 0x0004
Improve bulk-insert performance by keeping the current target buffer pinned (but not locked, as that would risk deadlocks). Also, make it work in a small ring of buffers to avoid having bulk inserts trash the whole buffer arena. Robert Haas, after an idea of Simon Riggs'.
2008-11-06 21:51:15 +01:00
typedef struct BulkInsertStateData *BulkInsertState;
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
/*
* Possible lock modes for a tuple.
*/
typedef enum LockTupleMode
Arrange for large sequential scans to synchronize with each other, so that when multiple backends are scanning the same relation concurrently, each page is (ideally) read only once. Jeff Davis, with review by Heikki and Tom.
2007-06-08 20:23:53 +02:00
{
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
/* SELECT FOR KEY SHARE */
LockTupleKeyShare,
/* SELECT FOR SHARE */
LockTupleShare,
/* SELECT FOR NO KEY UPDATE, and UPDATEs that don't modify key columns */
LockTupleNoKeyExclusive,
/* SELECT FOR UPDATE, UPDATEs that modify key columns, and DELETE */
Arrange for large sequential scans to synchronize with each other, so that when multiple backends are scanning the same relation concurrently, each page is (ideally) read only once. Jeff Davis, with review by Heikki and Tom.
2007-06-08 20:23:53 +02:00
LockTupleExclusive
} LockTupleMode;
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
#define MaxLockTupleMode LockTupleExclusive
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
/*
* When heap_update, heap_delete, or heap_lock_tuple fail because the target
* tuple is already outdated, they fill in this struct to provide information
* to the caller about what happened.
* ctid is the target's ctid link: it is the same as the target's TID if the
* target was deleted, or the location of the replacement tuple if the target
* was updated.
* xmax is the outdating transaction's XID. If the caller wants to visit the
* replacement tuple, it must check that this matches before believing the
* replacement is really a match.
* cmax is the outdating command's CID, but only when the failure code is
* HeapTupleSelfUpdated (i.e., something in the current transaction outdated
pgindent run for 9.4 This includes removing tabs after periods in C comments, which was applied to back branches, so this change should not effect backpatching.
2014-05-06 18:12:18 +02:00
* the tuple); otherwise cmax is zero. (We make this restriction because
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
* HeapTupleHeaderGetCmax doesn't work for tuples outdated in other
* transactions.)
*/
typedef struct HeapUpdateFailureData
{
pgindent run for release 9.3 This is the first run of the Perl-based pgindent script. Also update pgindent instructions.
2013-05-29 22:58:43 +02:00
ItemPointerData ctid;
TransactionId xmax;
CommandId cmax;
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
} HeapUpdateFailureData;
Arrange for large sequential scans to synchronize with each other, so that when multiple backends are scanning the same relation concurrently, each page is (ideally) read only once. Jeff Davis, with review by Heikki and Tom.
2007-06-08 20:23:53 +02:00
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
/* ----------------
Massive commit to run PGINDENT on all *.c and *.h files.
1997-09-07 07:04:48 +02:00
* function prototypes for heap access method
Reimplement nodeMaterial to use a temporary BufFile (or even memory, if the materialized tupleset is small enough) instead of a temporary relation. This was something I was thinking of doing anyway for performance, and Jan says he needs it for TOAST because he doesn't want to cope with toasting noname relations. With this change, the 'noname table' support in heap.c is dead code, and I have accordingly removed it. Also clean up 'noname' plan handling in planner --- nonames are either sort or materialize plans, and it seems less confusing to handle them separately under those names.
2000-06-19 00:44:35 +02:00
*
* heap_create, heap_create_with_catalog, and heap_drop_with_catalog
* are declared in catalog/heap.h
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
* ----------------
*/
Arrange for large sequential scans to synchronize with each other, so that when multiple backends are scanning the same relation concurrently, each page is (ideally) read only once. Jeff Davis, with review by Heikki and Tom.
2007-06-08 20:23:53 +02:00
/* in heap/heapam.c */
Fix problem reported by Alex Korn: if a relation has been dropped and recreated since the start of our transaction, our first reference to it errored out because we'd try to reuse our old relcache entry for it. Do this by accepting SI inval messages just before relcache search in heap_openr, so that dead relcache entries will be flushed before we search. Also, break heap_open/openr into two pairs of routines, relation_open(r) and heap_open(r). The relation_open routines make no tests on relkind and so can be used to open anything that has a pg_class entry. The heap_open routines are wrappers that add a relkind test to preserve their established behavior. Use the relation_open routines in several places that had various kluge solutions for opening rels that might be either heap or index rels. Also, remove the old 'heap stats' code that's been superseded by Jan's stats collector, and clean up some inconsistencies in error reporting between the different types of ALTER TABLE.
2001-11-02 17:30:29 +01:00
extern Relation relation_open(Oid relationId, LOCKMODE lockmode);
Now that we've rearranged relation open to get a lock before touching the rel, it's easy to get rid of the narrow race-condition window that used to exist in VACUUM and CLUSTER. Did some minor code-beautification work in the same area, too.
2006-08-18 18:09:13 +02:00
extern Relation try_relation_open(Oid relationId, LOCKMODE lockmode);
pg_class has a relnamespace column. You can create and access tables in schemas other than the system namespace; however, there's no search path yet, and not all operations work yet on tables outside the system namespace.
2002-03-26 20:17:02 +01:00
extern Relation relation_openrv(const RangeVar *relation, LOCKMODE lockmode);
Allow callers to pass a missing_ok flag when opening a relation. Since the names try_relation_openrv() and try_heap_openrv() don't seem quite appropriate, rename the functions to relation_openrv_extended() and heap_openrv_extended(). This is also more general, if we have a future need for additional parameters that are of interest to only a few callers. This is infrastructure for a forthcoming patch to allow get_object_address() to take a missing_ok argument as well. Patch by me, review by Noah Misch.
2011-06-27 21:06:32 +02:00
extern Relation relation_openrv_extended(const RangeVar *relation,
LOCKMODE lockmode, bool missing_ok);
Fix problem reported by Alex Korn: if a relation has been dropped and recreated since the start of our transaction, our first reference to it errored out because we'd try to reuse our old relcache entry for it. Do this by accepting SI inval messages just before relcache search in heap_openr, so that dead relcache entries will be flushed before we search. Also, break heap_open/openr into two pairs of routines, relation_open(r) and heap_open(r). The relation_open routines make no tests on relkind and so can be used to open anything that has a pg_class entry. The heap_open routines are wrappers that add a relkind test to preserve their established behavior. Use the relation_open routines in several places that had various kluge solutions for opening rels that might be either heap or index rels. Also, remove the old 'heap stats' code that's been superseded by Jan's stats collector, and clean up some inconsistencies in error reporting between the different types of ALTER TABLE.
2001-11-02 17:30:29 +01:00
extern void relation_close(Relation relation, LOCKMODE lockmode);
Mega-commit to make heap_open/heap_openr/heap_close take an additional argument specifying the kind of lock to acquire/release (or 'NoLock' to do no lock processing). Ensure that all relations are locked with some appropriate lock level before being examined --- this ensures that relevant shared-inval messages have been processed and should prevent problems caused by concurrent VACUUM. Fix several bugs having to do with mismatched increment/decrement of relation ref count and mismatched heap_open/close (which amounts to the same thing). A bogus ref count on a relation doesn't matter much *unless* a SI Inval message happens to arrive at the wrong time, which is probably why we got away with this sloppiness for so long. Repair missing grab of AccessExclusiveLock in DROP TABLE, ALTER/RENAME TABLE, etc, as noted by Hiroshi. Recommend 'make clean all' after pulling this update; I modified the Relation struct layout slightly. Will post further discussion to pghackers list shortly.
1999-09-18 21:08:25 +02:00
extern Relation heap_open(Oid relationId, LOCKMODE lockmode);
pg_class has a relnamespace column. You can create and access tables in schemas other than the system namespace; however, there's no search path yet, and not all operations work yet on tables outside the system namespace.
2002-03-26 20:17:02 +01:00
extern Relation heap_openrv(const RangeVar *relation, LOCKMODE lockmode);
Allow callers to pass a missing_ok flag when opening a relation. Since the names try_relation_openrv() and try_heap_openrv() don't seem quite appropriate, rename the functions to relation_openrv_extended() and heap_openrv_extended(). This is also more general, if we have a future need for additional parameters that are of interest to only a few callers. This is infrastructure for a forthcoming patch to allow get_object_address() to take a missing_ok argument as well. Patch by me, review by Noah Misch.
2011-06-27 21:06:32 +02:00
extern Relation heap_openrv_extended(const RangeVar *relation,
LOCKMODE lockmode, bool missing_ok);
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 18:46:40 +01:00
Fix problem reported by Alex Korn: if a relation has been dropped and recreated since the start of our transaction, our first reference to it errored out because we'd try to reuse our old relcache entry for it. Do this by accepting SI inval messages just before relcache search in heap_openr, so that dead relcache entries will be flushed before we search. Also, break heap_open/openr into two pairs of routines, relation_open(r) and heap_open(r). The relation_open routines make no tests on relkind and so can be used to open anything that has a pg_class entry. The heap_open routines are wrappers that add a relkind test to preserve their established behavior. Use the relation_open routines in several places that had various kluge solutions for opening rels that might be either heap or index rels. Also, remove the old 'heap stats' code that's been superseded by Jan's stats collector, and clean up some inconsistencies in error reporting between the different types of ALTER TABLE.
2001-11-02 17:30:29 +01:00
#define heap_close(r,l) relation_close(r,l)
Improve our #include situation by moving pointer types away from the corresponding struct definitions. This allows other headers to avoid including certain highly-loaded headers such as rel.h and relscan.h, instead using just relcache.h, heapam.h or genam.h, which are more lightweight and thus cause less unnecessary dependencies.
2008-06-19 02:46:06 +02:00
/* struct definition appears in relscan.h */
typedef struct HeapScanDescData *HeapScanDesc;
/*
* HeapScanIsValid
* True iff the heap scan is valid.
*/
#define HeapScanIsValid(scan) PointerIsValid(scan)
Restructure indexscan API (index_beginscan, index_getnext) per yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
2002-05-21 01:51:44 +02:00
extern HeapScanDesc heap_beginscan(Relation relation, Snapshot snapshot,
pgindent run.
2002-09-04 22:31:48 +02:00
int nkeys, ScanKey key);
Use an MVCC snapshot, rather than SnapshotNow, for catalog scans. SnapshotNow scans have the undesirable property that, in the face of concurrent updates, the scan can fail to see either the old or the new versions of the row. In many cases, we work around this by requiring DDL operations to hold AccessExclusiveLock on the object being modified; in some cases, the existing locking is inadequate and random failures occur as a result. This commit doesn't change anything related to locking, but will hopefully pave the way to allowing lock strength reductions in the future. The major issue has held us back from making this change in the past is that taking an MVCC snapshot is significantly more expensive than using a static special snapshot such as SnapshotNow. However, testing of various worst-case scenarios reveals that this problem is not severe except under fairly extreme workloads. To mitigate those problems, we avoid retaking the MVCC snapshot for each new scan; instead, we take a new snapshot only when invalidation messages have been processed. The catcache machinery already requires that invalidation messages be sent before releasing the related heavyweight lock; else other backends might rely on locally-cached data rather than scanning the catalog at all. Thus, making snapshot reuse dependent on the same guarantees shouldn't break anything that wasn't already subtly broken. Patch by me. Review by Michael Paquier and Andres Freund.
2013-07-02 15:47:01 +02:00
extern HeapScanDesc heap_beginscan_catalog(Relation relation, int nkeys,
pgindent run for 9.4 This includes removing tabs after periods in C comments, which was applied to back branches, so this change should not effect backpatching.
2014-05-06 18:12:18 +02:00
ScanKey key);
Fix CREATE INDEX CONCURRENTLY so that it won't use synchronized scan for its second pass over the table. It has to start at block zero, else the "merge join" logic for detecting which TIDs are already in the index doesn't work. Hence, extend heapam.c's API so that callers can enable or disable syncscan. (I put in an option to disable buffer access strategy, too, just in case somebody needs it.) Per report from Hannes Dorbath.
2008-01-14 02:39:09 +01:00
extern HeapScanDesc heap_beginscan_strat(Relation relation, Snapshot snapshot,
int nkeys, ScanKey key,
bool allow_strat, bool allow_sync);
Teach heapam code to know the difference between a real seqscan and the pseudo HeapScanDesc created for a bitmap heap scan. This avoids some useless overhead during a bitmap scan startup, in particular invoking the syncscan code. (We might someday want to do that, but right now it's merely useless contention for shared memory, to say nothing of possibly pushing useful entries out of syncscan's small LRU list.) This also allows elimination of ugly pgstat_discount_heap_scan() kluge.
2007-06-09 20:49:55 +02:00
extern HeapScanDesc heap_beginscan_bm(Relation relation, Snapshot snapshot,
pgindent run for 8.3.
2007-11-15 22:14:46 +01:00
int nkeys, ScanKey key);
Restructure indexscan API (index_beginscan, index_getnext) per yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
2002-05-21 01:51:44 +02:00
extern void heap_rescan(HeapScanDesc scan, ScanKey key);
heap_fetch requires buffer pointer, must be released; heap_getnext no longer returns buffer pointer, can be gotten from scan; descriptor; bootstrap can create multi-key indexes; pg_procname index now is multi-key index; oidint2, oidint4, oidname are gone (must be removed from regression tests); use System Cache rather than sequential scan in many places; heap_modifytuple no longer takes buffer parameter; remove unused buffer parameter in a few other functions; oid8 is not index-able; remove some use of single-character variable names; cleanup Buffer variables usage and scan descriptor looping; cleaned up allocation and freeing of tuples; 18k lines of diff;
1998-08-19 04:04:17 +02:00
extern void heap_endscan(HeapScanDesc scan);
Restructure indexscan API (index_beginscan, index_getnext) per yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
2002-05-21 01:51:44 +02:00
extern HeapTuple heap_getnext(HeapScanDesc scan, ScanDirection direction);
Mark index entries "killed" when they are no longer visible to any transaction, so as to avoid returning them out of the index AM. Saves repeated heap_fetch operations on frequently-updated rows. Also detect queries on unique keys (equality to all columns of a unique index), and don't bother continuing scan once we have found first match. Killing is implemented in the btree and hash AMs, but not yet in rtree or gist, because there isn't an equally convenient place to do it in those AMs (the outer amgetnext routine can't do it without re-pinning the index page). Did some small cleanup on APIs of HeapTupleSatisfies, heap_fetch, and index_insert to make this a little easier.
2002-05-24 20:57:57 +02:00
extern bool heap_fetch(Relation relation, Snapshot snapshot,
pgindent run.
2002-09-04 22:31:48 +02:00
HeapTuple tuple, Buffer *userbuf, bool keep_buf,
Fix up pgstats counting of live and dead tuples to recognize that committed and aborted transactions have different effects; also teach it not to assume that prepared transactions are always committed. Along the way, simplify the pgstats API by tying counting directly to Relations; I cannot detect any redeeming social value in having stats pointers in HeapScanDesc and IndexScanDesc structures. And fix a few corner cases in which counts might be missed because the relation's pgstat_info pointer hadn't been set.
2007-05-27 05:50:39 +02:00
Relation stats_relation);
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
extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
Avoid having two copies of the HOT-chain search logic. It's been like this since HOT was originally introduced, but the logic is complex enough that this is a recipe for bugs, as we've already found out with SSI. So refactor heap_hot_search_buffer() so that it can satisfy the needs of index_getnext(), and make index_getnext() use that rather than duplicating the logic. This change was originally proposed by Heikki Linnakangas as part of a larger refactoring oriented towards allowing index-only scans. I extracted and adjusted this part, since it seems to have independent merit. Review by Jeff Davis.
2011-06-27 16:27:17 +02:00
Buffer buffer, Snapshot snapshot, HeapTuple heapTuple,
bool *all_dead, bool first_call);
HOT updates. When we update a tuple without changing any of its indexed columns, and the new version can be stored on the same heap page, we no longer generate extra index entries for the new version. Instead, index searches follow the HOT-chain links to ensure they find the correct tuple version. In addition, this patch introduces the ability to "prune" dead tuples on a per-page basis, without having to do a complete VACUUM pass to recover space. VACUUM is still needed to clean up dead index entries, however. Pavan Deolasee, with help from a bunch of other people.
2007-09-20 19:56:33 +02:00
extern bool heap_hot_search(ItemPointer tid, Relation relation,
pgindent run for 8.3.
2007-11-15 22:14:46 +01:00
Snapshot snapshot, bool *all_dead);
Restructure indexscan API (index_beginscan, index_getnext) per yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
2002-05-21 01:51:44 +02:00
Repair problems with VACUUM destroying t_ctid chains too soon, and with insufficient paranoia in code that follows t_ctid links. (We must do both because even with VACUUM doing it properly, the intermediate state with a dangling t_ctid link is visible concurrently during lazy VACUUM, and could be seen afterwards if either type of VACUUM crashes partway through.) Also try to improve documentation about what's going on. Patch is a bit bulky because passing the XMAX information around required changing the APIs of some low-level heapam.c routines, but it's not conceptually very complicated. Per trouble report from Teodor and subsequent analysis. This needs to be back-patched, but I'll do that after 8.1 beta is out.
2005-08-20 02:40:32 +02:00
extern void heap_get_latest_tid(Relation relation, Snapshot snapshot,
pgindent run.
2002-09-04 22:31:48 +02:00
ItemPointer tid);
Suppress compiler warning.
2001-09-17 02:29:10 +02:00
extern void setLastTid(const ItemPointer tid);
Remove global variable scanCommandId in favor of storing a command ID in snapshots, per my proposal of a few days ago. Also, tweak heapam.c routines (heap_insert, heap_update, heap_delete, heap_mark4update) to be passed the command ID to use, instead of doing GetCurrentCommandID. For catalog updates they'll still get passed current command ID, but for updates generated from the main executor they'll get passed the command ID saved in the snapshot the query is using. This should fix some corner cases associated with functions and triggers that advance current command ID while an outer query is still in progress.
2002-05-22 00:05:55 +02:00
Improve bulk-insert performance by keeping the current target buffer pinned (but not locked, as that would risk deadlocks). Also, make it work in a small ring of buffers to avoid having bulk inserts trash the whole buffer arena. Robert Haas, after an idea of Simon Riggs'.
2008-11-06 21:51:15 +01:00
extern BulkInsertState GetBulkInsertState(void);
extern void FreeBulkInsertState(BulkInsertState);
Standard pgindent run for 8.1.
2005-10-15 04:49:52 +02:00
extern Oid heap_insert(Relation relation, HeapTuple tup, CommandId cid,
Improve bulk-insert performance by keeping the current target buffer pinned (but not locked, as that would risk deadlocks). Also, make it work in a small ring of buffers to avoid having bulk inserts trash the whole buffer arena. Robert Haas, after an idea of Simon Riggs'.
2008-11-06 21:51:15 +01:00
int options, BulkInsertState bistate);
In COPY, insert tuples to the heap in batches. This greatly reduces the WAL volume, especially when the table is narrow. The overhead of locking the heap page is also reduced. Reduced WAL traffic also makes it scale a lot better, if you run multiple COPY processes at the same time.
2011-11-09 09:54:41 +01:00
extern void heap_multi_insert(Relation relation, HeapTuple *tuples, int ntuples,
CommandId cid, int options, BulkInsertState bistate);
Repair problems with VACUUM destroying t_ctid chains too soon, and with insufficient paranoia in code that follows t_ctid links. (We must do both because even with VACUUM doing it properly, the intermediate state with a dangling t_ctid link is visible concurrently during lazy VACUUM, and could be seen afterwards if either type of VACUUM crashes partway through.) Also try to improve documentation about what's going on. Patch is a bit bulky because passing the XMAX information around required changing the APIs of some low-level heapam.c routines, but it's not conceptually very complicated. Per trouble report from Teodor and subsequent analysis. This needs to be back-patched, but I'll do that after 8.1 beta is out.
2005-08-20 02:40:32 +02:00
extern HTSU_Result heap_delete(Relation relation, ItemPointer tid,
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
CommandId cid, Snapshot crosscheck, bool wait,
HeapUpdateFailureData *hufd);
Repair problems with VACUUM destroying t_ctid chains too soon, and with insufficient paranoia in code that follows t_ctid links. (We must do both because even with VACUUM doing it properly, the intermediate state with a dangling t_ctid link is visible concurrently during lazy VACUUM, and could be seen afterwards if either type of VACUUM crashes partway through.) Also try to improve documentation about what's going on. Patch is a bit bulky because passing the XMAX information around required changing the APIs of some low-level heapam.c routines, but it's not conceptually very complicated. Per trouble report from Teodor and subsequent analysis. This needs to be back-patched, but I'll do that after 8.1 beta is out.
2005-08-20 02:40:32 +02:00
extern HTSU_Result heap_update(Relation relation, ItemPointer otid,
Standard pgindent run for 8.1.
2005-10-15 04:49:52 +02:00
HeapTuple newtup,
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
CommandId cid, Snapshot crosscheck, bool wait,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
HeapUpdateFailureData *hufd, LockTupleMode *lockmode);
Repair problems with VACUUM destroying t_ctid chains too soon, and with insufficient paranoia in code that follows t_ctid links. (We must do both because even with VACUUM doing it properly, the intermediate state with a dangling t_ctid link is visible concurrently during lazy VACUUM, and could be seen afterwards if either type of VACUUM crashes partway through.) Also try to improve documentation about what's going on. Patch is a bit bulky because passing the XMAX information around required changing the APIs of some low-level heapam.c routines, but it's not conceptually very complicated. Per trouble report from Teodor and subsequent analysis. This needs to be back-patched, but I'll do that after 8.1 beta is out.
2005-08-20 02:40:32 +02:00
extern HTSU_Result heap_lock_tuple(Relation relation, HeapTuple tuple,
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
CommandId cid, LockTupleMode mode, bool nowait,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
bool follow_update,
Throw error if expiring tuple is again updated or deleted. This prevents surprising behavior when a FOR EACH ROW trigger BEFORE UPDATE or BEFORE DELETE directly or indirectly updates or deletes the the old row. Prior to this patch the requested action on the row could be silently ignored while all triggered actions based on the occurence of the requested action could be committed. One example of how this could happen is if the BEFORE DELETE trigger for a "parent" row deleted "children" which had trigger functions to update summary or status data on the parent. This also prevents similar surprising problems if the query has a volatile function which updates a target row while it is already being updated. There are related issues present in FOR UPDATE cursors and READ COMMITTED queries which are not handled by this patch. These issues need further evalution to determine what change, if any, is needed. Where the new error messages are generated, in most cases the best fix will be to move code from the BEFORE trigger to an AFTER trigger. Where this is not feasible, the trigger can avoid the error by re-issuing the triggering statement and returning NULL. Documentation changes will be submitted in a separate patch. Kevin Grittner and Tom Lane with input from Florian Pflug and Robert Haas, based on problems encountered during conversion of Wisconsin Circuit Court trigger logic to plpgsql triggers.
2012-10-26 21:55:36 +02:00
Buffer *buffer, HeapUpdateFailureData *hufd);
Clean up code associated with updating pg_class statistics columns (relpages/reltuples). To do this, create formal support in heapam.c for "overwrite" tuple updates (including xlog replay capability) and use that instead of the ad-hoc overwrites we'd been using in VACUUM and CREATE INDEX. Take the responsibility for updating stats during CREATE INDEX out of the individual index AMs, and do it where it belongs, in catalog/index.c. Aside from being more modular, this avoids having to update the same tuple twice in some paths through CREATE INDEX. It's probably not measurably faster, but for sure it's a lot cleaner than before.
2006-05-11 01:18:39 +02:00
extern void heap_inplace_update(Relation relation, HeapTuple tuple);
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
extern bool heap_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
TransactionId cutoff_multi);
Make VACUUM avoid waiting for a cleanup lock, where possible. In a regular VACUUM, it's OK to skip pages for which a cleanup lock isn't immediately available; the next VACUUM will deal with them. If we're scanning the entire relation to advance relfrozenxid, we might need to wait, but only if there are tuples on the page that actually require freezing. These changes should greatly reduce the incidence of of vacuum processes getting "stuck". Simon Riggs and Robert Haas
2011-11-08 03:39:40 +01:00
extern bool heap_tuple_needs_freeze(HeapTupleHeader tuple, TransactionId cutoff_xid,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
MultiXactId cutoff_multi, Buffer buf);
Remove global variable scanCommandId in favor of storing a command ID in snapshots, per my proposal of a few days ago. Also, tweak heapam.c routines (heap_insert, heap_update, heap_delete, heap_mark4update) to be passed the command ID to use, instead of doing GetCurrentCommandID. For catalog updates they'll still get passed current command ID, but for updates generated from the main executor they'll get passed the command ID saved in the snapshot the query is using. This should fix some corner cases associated with functions and triggers that advance current command ID while an outer query is still in progress.
2002-05-22 00:05:55 +02:00
extern Oid simple_heap_insert(Relation relation, HeapTuple tup);
Fix all the places that called heap_update() and heap_delete() without bothering to check the return value --- which meant that in case the update or delete failed because of a concurrent update, you'd not find out about it, except by observing later that the transaction produced the wrong outcome. There are now subroutines simple_heap_update and simple_heap_delete that should be used anyplace that you're not prepared to do the full nine yards of coping with concurrent updates. In practice, that seems to mean absolutely everywhere but the executor, because *noplace* else was checking.
2001-01-23 05:32:23 +01:00
extern void simple_heap_delete(Relation relation, ItemPointer tid);
extern void simple_heap_update(Relation relation, ItemPointer otid,
pgindent run. Make it all clean.
2001-03-22 05:01:46 +01:00
HeapTuple tup);
Remove global variable scanCommandId in favor of storing a command ID in snapshots, per my proposal of a few days ago. Also, tweak heapam.c routines (heap_insert, heap_update, heap_delete, heap_mark4update) to be passed the command ID to use, instead of doing GetCurrentCommandID. For catalog updates they'll still get passed current command ID, but for updates generated from the main executor they'll get passed the command ID saved in the snapshot the query is using. This should fix some corner cases associated with functions and triggers that advance current command ID while an outer query is still in progress.
2002-05-22 00:05:55 +02:00
heap_fetch requires buffer pointer, must be released; heap_getnext no longer returns buffer pointer, can be gotten from scan; descriptor; bootstrap can create multi-key indexes; pg_procname index now is multi-key index; oidint2, oidint4, oidname are gone (must be removed from regression tests); use System Cache rather than sequential scan in many places; heap_modifytuple no longer takes buffer parameter; remove unused buffer parameter in a few other functions; oid8 is not index-able; remove some use of single-character variable names; cleanup Buffer variables usage and scan descriptor looping; cleaned up allocation and freeing of tuples; 18k lines of diff;
1998-08-19 04:04:17 +02:00
extern void heap_markpos(HeapScanDesc scan);
extern void heap_restrpos(HeapScanDesc scan);
Moved from backend/access to include/access
1996-08-27 23:50:29 +02:00
HOT updates. When we update a tuple without changing any of its indexed columns, and the new version can be stored on the same heap page, we no longer generate extra index entries for the new version. Instead, index searches follow the HOT-chain links to ensure they find the correct tuple version. In addition, this patch introduces the ability to "prune" dead tuples on a per-page basis, without having to do a complete VACUUM pass to recover space. VACUUM is still needed to clean up dead index entries, however. Pavan Deolasee, with help from a bunch of other people.
2007-09-20 19:56:33 +02:00
extern void heap_sync(Relation relation);
/* in heap/pruneheap.c */
Introduce logical decoding. This feature, building on previous commits, allows the write-ahead log stream to be decoded into a series of logical changes; that is, inserts, updates, and deletes and the transactions which contain them. It is capable of handling decoding even across changes to the schema of the effected tables. The output format is controlled by a so-called "output plugin"; an example is included. To make use of this in a real replication system, the output plugin will need to be modified to produce output in the format appropriate to that system, and to perform filtering. Currently, information can be extracted from the logical decoding system only via SQL; future commits will add the ability to stream changes via walsender. Andres Freund, with review and other contributions from many other people, including Álvaro Herrera, Abhijit Menon-Sen, Peter Gheogegan, Kevin Grittner, Robert Haas, Heikki Linnakangas, Fujii Masao, Abhijit Menon-Sen, Michael Paquier, Simon Riggs, Craig Ringer, and Steve Singer.
2014-03-03 22:32:18 +01:00
extern void heap_page_prune_opt(Relation relation, Buffer buffer);
pgindent run for 8.3.
2007-11-15 22:14:46 +01:00
extern int heap_page_prune(Relation relation, Buffer buffer,
TransactionId OldestXmin,
Fix oversight in collecting values for cleanup_info records. vacuum_log_cleanup_info() now generates log records with a valid latestRemovedXid set in all cases. Also be careful not to zero the value when we do a round of vacuuming part-way through lazy_scan_heap(). Incidentally, this reduces frequency of conflicts in Hot Standby.
2010-04-21 19:20:56 +02:00
bool report_stats, TransactionId *latestRemovedXid);
Refactor XLogOpenRelation() and XLogReadBuffer() in preparation for relation forks. XLogOpenRelation() and the associated light-weight relation cache in xlogutils.c is gone, and XLogReadBuffer() now takes a RelFileNode as argument, instead of Relation. For functions that still need a Relation struct during WAL replay, there's a new function called CreateFakeRelcacheEntry() that returns a fake entry like XLogOpenRelation() used to.
2008-06-12 11:12:31 +02:00
extern void heap_page_prune_execute(Buffer buffer,
Refactor heap_page_prune so that instead of changing item states on-the-fly, it accumulates the set of changes to be made and then applies them. It had to accumulate the set of changes anyway to prepare a WAL record for the pruning action, so this isn't an enormous change; the only new complexity is to not doubly mark tuples that are visited twice in the scan. The main advantage is that we can substantially reduce the scope of the critical section in which the changes are applied, thus avoiding PANIC in foreseeable cases like running out of memory in inval.c. A nice secondary advantage is that it is now far clearer that WAL replay will actually do the same thing that the original pruning did. This commit doesn't do anything about the open problem that CacheInvalidateHeapTuple doesn't have the right semantics for a CTID change caused by collapsing out a redirect pointer. But whatever we do about that, it'll be a good idea to not do it inside a critical section.
2008-03-08 22:57:59 +01:00
OffsetNumber *redirected, int nredirected,
OffsetNumber *nowdead, int ndead,
Remove old-style VACUUM FULL (which was known for a little while as VACUUM FULL INPLACE), along with a boatload of subsidiary code and complexity. Per discussion, the use case for this method of vacuuming is no longer large enough to justify maintaining it; not to mention that we don't wish to invest the work that would be needed to make it play nicely with Hot Standby. Aside from the code directly related to old-style VACUUM FULL, this commit removes support for certain WAL record types that could only be generated within VACUUM FULL, redirect-pointer removal in heap_page_prune, and nontransactional generation of cache invalidation sinval messages (the last being the sticking point for Hot Standby). We still have to retain all code that copes with finding HEAP_MOVED_OFF and HEAP_MOVED_IN flag bits on existing tuples. This can't be removed as long as we want to support in-place update from pre-9.0 databases.
2010-02-08 05:33:55 +01:00
OffsetNumber *nowunused, int nunused);
HOT updates. When we update a tuple without changing any of its indexed columns, and the new version can be stored on the same heap page, we no longer generate extra index entries for the new version. Instead, index searches follow the HOT-chain links to ensure they find the correct tuple version. In addition, this patch introduces the ability to "prune" dead tuples on a per-page basis, without having to do a complete VACUUM pass to recover space. VACUUM is still needed to clean up dead index entries, however. Pavan Deolasee, with help from a bunch of other people.
2007-09-20 19:56:33 +02:00
extern void heap_get_root_tuples(Page page, OffsetNumber *root_offsets);
Prevent WAL logging when COPY is done in the same transation that created it. Simon Riggs
2007-01-25 03:17:26 +01:00
Arrange for large sequential scans to synchronize with each other, so that when multiple backends are scanning the same relation concurrently, each page is (ideally) read only once. Jeff Davis, with review by Heikki and Tom.
2007-06-08 20:23:53 +02:00
/* in heap/syncscan.c */
extern void ss_report_location(Relation rel, BlockNumber location);
extern BlockNumber ss_get_location(Relation rel, BlockNumber relnblocks);
extern void SyncScanShmemInit(void);
extern Size SyncScanShmemSize(void);
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 18:46:40 +01:00
#endif /* HEAPAM_H */