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928408d9e5
If there's a dangerous structure T0 ---> T1 ---> T2, and T2 commits first, we need to abort something. If T2 commits before both conflicts appear, then it should be caught by OnConflict_CheckForSerializationFailure. If both conflicts appear before T2 commits, it should be caught by PreCommit_CheckForSerializationFailure. But that is actually run when T2 *prepares*. Fix that in OnConflict_CheckForSerializationFailure, by treating a prepared T2 as if it committed already. This is mostly a problem for prepared transactions, which are in prepared state for some time, but also for regular transactions because they also go through the prepared state in the SSI code for a short moment when they're committed. Kevin Grittner and Dan Ports
159 lines
3.8 KiB
SQL
159 lines
3.8 KiB
SQL
--
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-- PREPARED TRANSACTIONS (two-phase commit)
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--
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-- We can't readily test persistence of prepared xacts within the
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-- regression script framework, unfortunately. Note that a crash
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-- isn't really needed ... stopping and starting the postmaster would
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-- be enough, but we can't even do that here.
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-- create a simple table that we'll use in the tests
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CREATE TABLE pxtest1 (foobar VARCHAR(10));
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INSERT INTO pxtest1 VALUES ('aaa');
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-- Test PREPARE TRANSACTION
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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UPDATE pxtest1 SET foobar = 'bbb' WHERE foobar = 'aaa';
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SELECT * FROM pxtest1;
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PREPARE TRANSACTION 'foo1';
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SELECT * FROM pxtest1;
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-- Test pg_prepared_xacts system view
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SELECT gid FROM pg_prepared_xacts;
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-- Test ROLLBACK PREPARED
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ROLLBACK PREPARED 'foo1';
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SELECT * FROM pxtest1;
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SELECT gid FROM pg_prepared_xacts;
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-- Test COMMIT PREPARED
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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INSERT INTO pxtest1 VALUES ('ddd');
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SELECT * FROM pxtest1;
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PREPARE TRANSACTION 'foo2';
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SELECT * FROM pxtest1;
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COMMIT PREPARED 'foo2';
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SELECT * FROM pxtest1;
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-- Test duplicate gids
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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UPDATE pxtest1 SET foobar = 'eee' WHERE foobar = 'ddd';
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SELECT * FROM pxtest1;
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PREPARE TRANSACTION 'foo3';
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SELECT gid FROM pg_prepared_xacts;
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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INSERT INTO pxtest1 VALUES ('fff');
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-- This should fail, because the gid foo3 is already in use
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PREPARE TRANSACTION 'foo3';
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SELECT * FROM pxtest1;
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ROLLBACK PREPARED 'foo3';
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SELECT * FROM pxtest1;
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-- Test serialization failure (SSI)
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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UPDATE pxtest1 SET foobar = 'eee' WHERE foobar = 'ddd';
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SELECT * FROM pxtest1;
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PREPARE TRANSACTION 'foo4';
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SELECT gid FROM pg_prepared_xacts;
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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SELECT * FROM pxtest1;
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-- This should fail, because the two transactions have a write-skew anomaly
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INSERT INTO pxtest1 VALUES ('fff');
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PREPARE TRANSACTION 'foo5';
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SELECT gid FROM pg_prepared_xacts;
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ROLLBACK PREPARED 'foo4';
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SELECT gid FROM pg_prepared_xacts;
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-- Clean up
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DROP TABLE pxtest1;
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-- Test subtransactions
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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CREATE TABLE pxtest2 (a int);
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INSERT INTO pxtest2 VALUES (1);
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SAVEPOINT a;
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INSERT INTO pxtest2 VALUES (2);
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ROLLBACK TO a;
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SAVEPOINT b;
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INSERT INTO pxtest2 VALUES (3);
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PREPARE TRANSACTION 'regress-one';
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CREATE TABLE pxtest3(fff int);
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-- Test shared invalidation
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BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
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DROP TABLE pxtest3;
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CREATE TABLE pxtest4 (a int);
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INSERT INTO pxtest4 VALUES (1);
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INSERT INTO pxtest4 VALUES (2);
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DECLARE foo CURSOR FOR SELECT * FROM pxtest4;
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-- Fetch 1 tuple, keeping the cursor open
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FETCH 1 FROM foo;
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PREPARE TRANSACTION 'regress-two';
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-- No such cursor
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FETCH 1 FROM foo;
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-- Table doesn't exist, the creation hasn't been committed yet
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SELECT * FROM pxtest2;
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-- There should be two prepared transactions
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SELECT gid FROM pg_prepared_xacts;
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-- pxtest3 should be locked because of the pending DROP
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set statement_timeout to 2000;
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SELECT * FROM pxtest3;
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reset statement_timeout;
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-- Disconnect, we will continue testing in a different backend
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\c -
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-- There should still be two prepared transactions
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SELECT gid FROM pg_prepared_xacts;
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-- pxtest3 should still be locked because of the pending DROP
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set statement_timeout to 2000;
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SELECT * FROM pxtest3;
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reset statement_timeout;
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-- Commit table creation
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COMMIT PREPARED 'regress-one';
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\d pxtest2
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SELECT * FROM pxtest2;
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-- There should be one prepared transaction
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SELECT gid FROM pg_prepared_xacts;
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-- Commit table drop
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COMMIT PREPARED 'regress-two';
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SELECT * FROM pxtest3;
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-- There should be no prepared transactions
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SELECT gid FROM pg_prepared_xacts;
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-- Clean up
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DROP TABLE pxtest2;
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DROP TABLE pxtest3; -- will still be there if prepared xacts are disabled
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DROP TABLE pxtest4;
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