Re: Transactions and temp tables - Mailing list pgsql-hackers
| From | Emmanuel Cecchet |
|---|---|
| Subject | Re: Transactions and temp tables |
| Date | |
| Msg-id | 48EC14C8.4000805@frogthinker.org Whole thread Raw |
| In response to | Re: Transactions and temp tables (David Fetter <david@fetter.org>) |
| List | pgsql-hackers |
Hi, Here are the patches for 8.4 (1 patch for the code and 1 patch for the regression tests). Thanks in advance for your feedback, Emmanuel David Fetter wrote: > On Tue, Oct 07, 2008 at 06:12:14PM -0400, Emmanuel Cecchet wrote: > >> Hi, >> >> >>> On Tue, Oct 07, 2008 at 04:57:37PM -0400, Emmanuel Cecchet wrote: >>> >>> >>>> Heikki, >>>> >>>> Here is a new version of the patch using a hash table as you >>>> suggested. I also include the tests that I have added to the >>>> regression test suite to test the various scenarios. All patches >>>> are based on Postgres 8.3.3, let me know if you want me to >>>> generate patch for 8.4. >>>> >>> CVS TIP is the only place where new features, like this, go :) >>> >>> >> I looked at the Wiki and it looks like I should add en entry >> (assuming I get a patch for the current CVS HEAD) to CommitFest >> 2008-11. Is that correct? >> >> >>> I didn't see the attachment anyhow... >>> >>> >> Good point! The same with the attachments now! >> > > Perhaps we did not make this clear. The patch is a new feature. New > features are not going into 8.3, as it has already been released. > > Make a patch against CVS TIP aka 8.4, and re-submit. > > Cheers, > David > -- Emmanuel Cecchet FTO @ Frog Thinker Open Source Development & Consulting -- Web: http://www.frogthinker.org email: manu@frogthinker.org Skype: emmanuel_cecchet ### Eclipse Workspace Patch 1.0 #P Postgres-HEAD Index: src/test/regress/parallel_schedule =================================================================== RCS file: /root/cvsrepo/pgsql/src/test/regress/parallel_schedule,v retrieving revision 1.46 diff -u -r1.46 parallel_schedule --- src/test/regress/parallel_schedule 24 Nov 2007 19:49:23 -0000 1.46 +++ src/test/regress/parallel_schedule 7 Oct 2008 23:41:14 -0000 @@ -90,3 +90,11 @@ # run tablespace by itself test: tablespace + +# -------- +# 2PC related tests +# -------- +test: 2pc_persistent_table 2pc_on_delete_rows_transaction 2pc_on_commit_drop 2pc_temp_table_transaction 2pc_temp_table_rollback2pc_temp_table_savepoint 2pc_temp_table_failure +test: 2pc_dirty_buffer_check +test: 2pc_temp_table_session +test: 2pc_on_delete_rows_session \ No newline at end of file Index: src/test/regress/serial_schedule =================================================================== RCS file: /root/cvsrepo/pgsql/src/test/regress/serial_schedule,v retrieving revision 1.43 diff -u -r1.43 serial_schedule --- src/test/regress/serial_schedule 24 Nov 2007 20:41:35 -0000 1.43 +++ src/test/regress/serial_schedule 7 Oct 2008 23:41:14 -0000 @@ -115,3 +115,13 @@ test: xml test: stats test: tablespace +test: 2pc_persistent_table +test: 2pc_on_delete_rows_transaction +test: 2pc_on_commit_drop +test: 2pc_temp_table_transaction +test: 2pc_temp_table_rollback +test: 2pc_temp_table_savepoint +test: 2pc_dirty_buffer_check +test: 2pc_temp_table_session +test: 2pc_on_delete_rows_session +test: 2pc_temp_table_failure \ No newline at end of file Index: src/test/regress/sql/2pc_on_delete_rows_transaction.sql =================================================================== RCS file: src/test/regress/sql/2pc_on_delete_rows_transaction.sql diff -N src/test/regress/sql/2pc_on_delete_rows_transaction.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_on_delete_rows_transaction.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,7 @@ +-- Temp table with ON DELETE ROWS option (transaction scope) +begin; +create temp table foo(x int) on commit delete rows; +insert into foo values(1); +prepare transaction 'onCommitDeleteRowsTempTableShouldSucceed'; +commit prepared 'onCommitDeleteRowsTempTableShouldSucceed'; +drop table foo; Index: src/test/regress/expected/2pc_on_commit_drop.out =================================================================== RCS file: src/test/regress/expected/2pc_on_commit_drop.out diff -N src/test/regress/expected/2pc_on_commit_drop.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_on_commit_drop.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,6 @@ +-- Temp table with ON COMMIT DROP option +begin; +create temp table foo(x int) on commit drop; +insert into foo values(1); +prepare transaction 'onCommitDropTempTableShouldSucceed'; +commit prepared 'onCommitDropTempTableShouldSucceed'; Index: src/test/regress/expected/2pc_temp_table_transaction.out =================================================================== RCS file: src/test/regress/expected/2pc_temp_table_transaction.out diff -N src/test/regress/expected/2pc_temp_table_transaction.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_temp_table_transaction.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,7 @@ +-- Transaction-scope dropped temp table use case +begin; +create temp table foo(x int); +insert into foo values(1); +drop table foo; +prepare transaction 'dropTempTableShouldSucceed'; +commit prepared 'dropTempTableShouldSucceed'; Index: src/test/regress/sql/2pc_temp_table_failure.sql =================================================================== RCS file: src/test/regress/sql/2pc_temp_table_failure.sql diff -N src/test/regress/sql/2pc_temp_table_failure.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_temp_table_failure.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,6 @@ +-- Existing non-empty temp table at commit time should still fail +begin; +create temp table foo(x int); +insert into foo values(1); +prepare transaction 'existingTempTableShouldFail'; +commit prepared 'existingTempTableShouldFail'; Index: src/test/regress/expected/2pc_temp_table_savepoint.out =================================================================== RCS file: src/test/regress/expected/2pc_temp_table_savepoint.out diff -N src/test/regress/expected/2pc_temp_table_savepoint.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_temp_table_savepoint.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,8 @@ +-- Rollback to savepoint test case +BEGIN; +SAVEPOINT sp; +CREATE TEMP TABLE foo(bar int4); +INSERT INTO foo VALUES (1); +ROLLBACK TO sp; +PREPARE TRANSACTION 'savepointTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; +COMMIT PREPARED 'savepointTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; Index: src/test/regress/sql/2pc_temp_table_transaction.sql =================================================================== RCS file: src/test/regress/sql/2pc_temp_table_transaction.sql diff -N src/test/regress/sql/2pc_temp_table_transaction.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_temp_table_transaction.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,7 @@ +-- Transaction-scope dropped temp table use case +begin; +create temp table foo(x int); +insert into foo values(1); +drop table foo; +prepare transaction 'dropTempTableShouldSucceed'; +commit prepared 'dropTempTableShouldSucceed'; Index: src/test/regress/expected/2pc_temp_table_failure.out =================================================================== RCS file: src/test/regress/expected/2pc_temp_table_failure.out diff -N src/test/regress/expected/2pc_temp_table_failure.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_temp_table_failure.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,8 @@ +-- Existing non-empty temp table at commit time should still fail +begin; +create temp table foo(x int); +insert into foo values(1); +prepare transaction 'existingTempTableShouldFail'; +ERROR: cannot PREPARE a transaction that has operated on temporary tables that are not empty at commit time +commit prepared 'existingTempTableShouldFail'; +ERROR: prepared transaction with identifier "existingTempTableShouldFail" does not exist Index: src/test/regress/sql/2pc_temp_table_session.sql =================================================================== RCS file: src/test/regress/sql/2pc_temp_table_session.sql diff -N src/test/regress/sql/2pc_temp_table_session.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_temp_table_session.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,8 @@ +-- Session-scope temp table use case +create temp table foo(x int); +begin; +insert into foo values(1); +delete from foo; +prepare transaction 'dropTempTableShouldSucceed'; +commit prepared 'dropTempTableShouldSucceed'; +drop table foo; Index: src/test/regress/expected/2pc_dirty_buffer_check.out =================================================================== RCS file: src/test/regress/expected/2pc_dirty_buffer_check.out diff -N src/test/regress/expected/2pc_dirty_buffer_check.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_dirty_buffer_check.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,52 @@ +-- 2PC Dirty buffer check +begin; +create temp table foo(a int, b int, c int) on commit drop; +insert into foo values(1,1,1); +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +prepare transaction 'bcd'; +commit prepared 'bcd'; +begin; +create temp table bar(a int, b int, c int) on commit drop; +insert into bar values(1,1,1); +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +commit; Index: src/test/regress/sql/2pc_on_commit_drop.sql =================================================================== RCS file: src/test/regress/sql/2pc_on_commit_drop.sql diff -N src/test/regress/sql/2pc_on_commit_drop.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_on_commit_drop.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,6 @@ +-- Temp table with ON COMMIT DROP option +begin; +create temp table foo(x int) on commit drop; +insert into foo values(1); +prepare transaction 'onCommitDropTempTableShouldSucceed'; +commit prepared 'onCommitDropTempTableShouldSucceed'; Index: src/test/regress/sql/2pc_temp_table_savepoint.sql =================================================================== RCS file: src/test/regress/sql/2pc_temp_table_savepoint.sql diff -N src/test/regress/sql/2pc_temp_table_savepoint.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_temp_table_savepoint.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,8 @@ +-- Rollback to savepoint test case +BEGIN; +SAVEPOINT sp; +CREATE TEMP TABLE foo(bar int4); +INSERT INTO foo VALUES (1); +ROLLBACK TO sp; +PREPARE TRANSACTION 'savepointTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; +COMMIT PREPARED 'savepointTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; Index: src/test/regress/sql/2pc_temp_table_rollback.sql =================================================================== RCS file: src/test/regress/sql/2pc_temp_table_rollback.sql diff -N src/test/regress/sql/2pc_temp_table_rollback.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_temp_table_rollback.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,5 @@ +-- Rollback prepared +BEGIN; +CREATE TEMP TABLE foo(bar int4); +PREPARE TRANSACTION 'rollbackTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; +ROLLBACK PREPARED 'rollbackTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; Index: src/test/regress/expected/2pc_on_delete_rows_session.out =================================================================== RCS file: src/test/regress/expected/2pc_on_delete_rows_session.out diff -N src/test/regress/expected/2pc_on_delete_rows_session.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_on_delete_rows_session.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,7 @@ +-- Temp table with ON DELETE ROWS option (session scope) +create temp table foo(x int) on commit delete rows; +begin; +insert into foo values(1); +prepare transaction 'onCommitDeleteRowsTempTableShouldSucceed'; +commit prepared 'onCommitDeleteRowsTempTableShouldSucceed'; +drop table foo; Index: src/test/regress/sql/2pc_persistent_table.sql =================================================================== RCS file: src/test/regress/sql/2pc_persistent_table.sql diff -N src/test/regress/sql/2pc_persistent_table.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_persistent_table.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,12 @@ +-- Creation of a persistent table (not temp) +begin; +create table paul(x int); +insert into paul values(1); +prepare transaction 'persistentTableShouldSucceed'; +commit prepared 'persistentTableShouldSucceed'; + +-- Drop of a persistent table (not temp) +begin; +drop table paul; +prepare transaction 'dropPersistentTableShouldSucceed'; +commit prepared 'dropPersistentTableShouldSucceed'; Index: src/test/regress/expected/2pc_temp_table_rollback.out =================================================================== RCS file: src/test/regress/expected/2pc_temp_table_rollback.out diff -N src/test/regress/expected/2pc_temp_table_rollback.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_temp_table_rollback.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,5 @@ +-- Rollback prepared +BEGIN; +CREATE TEMP TABLE foo(bar int4); +PREPARE TRANSACTION 'rollbackTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; +ROLLBACK PREPARED 'rollbackTestCase_archives.postgresql.org_pgsql-hackers_2008-03_msg00017.php'; Index: src/test/regress/sql/2pc_dirty_buffer_check.sql =================================================================== RCS file: src/test/regress/sql/2pc_dirty_buffer_check.sql diff -N src/test/regress/sql/2pc_dirty_buffer_check.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_dirty_buffer_check.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,52 @@ +-- 2PC Dirty buffer check +begin; +create temp table foo(a int, b int, c int) on commit drop; +insert into foo values(1,1,1); +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +insert into foo select * from foo; +prepare transaction 'bcd'; +commit prepared 'bcd'; +begin; +create temp table bar(a int, b int, c int) on commit drop; +insert into bar values(1,1,1); +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +insert into bar select * from bar; +commit; Index: src/test/regress/expected/2pc_persistent_table.out =================================================================== RCS file: src/test/regress/expected/2pc_persistent_table.out diff -N src/test/regress/expected/2pc_persistent_table.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_persistent_table.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,11 @@ +-- Creation of a persistent table (not temp) +begin; +create table paul(x int); +insert into paul values(1); +prepare transaction 'persistentTableShouldSucceed'; +commit prepared 'persistentTableShouldSucceed'; +-- Drop of a persistent table (not temp) +begin; +drop table paul; +prepare transaction 'dropPersistentTableShouldSucceed'; +commit prepared 'dropPersistentTableShouldSucceed'; Index: src/test/regress/expected/2pc_temp_table_session.out =================================================================== RCS file: src/test/regress/expected/2pc_temp_table_session.out diff -N src/test/regress/expected/2pc_temp_table_session.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_temp_table_session.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,8 @@ +-- Session-scope temp table use case +create temp table foo(x int); +begin; +insert into foo values(1); +delete from foo; +prepare transaction 'dropTempTableShouldSucceed'; +commit prepared 'dropTempTableShouldSucceed'; +drop table foo; Index: src/test/regress/sql/2pc_on_delete_rows_session.sql =================================================================== RCS file: src/test/regress/sql/2pc_on_delete_rows_session.sql diff -N src/test/regress/sql/2pc_on_delete_rows_session.sql --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/sql/2pc_on_delete_rows_session.sql 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,7 @@ +-- Temp table with ON DELETE ROWS option (session scope) +create temp table foo(x int) on commit delete rows; +begin; +insert into foo values(1); +prepare transaction 'onCommitDeleteRowsTempTableShouldSucceed'; +commit prepared 'onCommitDeleteRowsTempTableShouldSucceed'; +drop table foo; Index: src/test/regress/expected/2pc_on_delete_rows_transaction.out =================================================================== RCS file: src/test/regress/expected/2pc_on_delete_rows_transaction.out diff -N src/test/regress/expected/2pc_on_delete_rows_transaction.out --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ src/test/regress/expected/2pc_on_delete_rows_transaction.out 1 Jan 1970 00:00:00 -0000 @@ -0,0 +1,7 @@ +-- Temp table with ON DELETE ROWS option (transaction scope) +begin; +create temp table foo(x int) on commit delete rows; +insert into foo values(1); +prepare transaction 'onCommitDeleteRowsTempTableShouldSucceed'; +commit prepared 'onCommitDeleteRowsTempTableShouldSucceed'; +drop table foo; ### Eclipse Workspace Patch 1.0 #P Postgres-HEAD Index: src/backend/access/heap/heapam.c =================================================================== RCS file: /root/cvsrepo/pgsql/src/backend/access/heap/heapam.c,v retrieving revision 1.264 diff -u -r1.264 heapam.c --- src/backend/access/heap/heapam.c 30 Sep 2008 10:52:10 -0000 1.264 +++ src/backend/access/heap/heapam.c 8 Oct 2008 01:53:44 -0000 @@ -878,7 +878,7 @@ /* Make note that we've accessed a temporary relation */ if (r->rd_istemp) - MyXactAccessedTempRel = true; + enlistRelationIdFor2PCChecks(relationId); pgstat_initstats(r); @@ -926,7 +926,7 @@ /* Make note that we've accessed a temporary relation */ if (r->rd_istemp) - MyXactAccessedTempRel = true; + enlistRelationIdFor2PCChecks(relationId); pgstat_initstats(r); @@ -976,7 +976,7 @@ /* Make note that we've accessed a temporary relation */ if (r->rd_istemp) - MyXactAccessedTempRel = true; + enlistRelationIdFor2PCChecks(relationId); pgstat_initstats(r); Index: src/backend/access/transam/xact.c =================================================================== RCS file: /root/cvsrepo/pgsql/src/backend/access/transam/xact.c,v retrieving revision 1.265 diff -u -r1.265 xact.c --- src/backend/access/transam/xact.c 11 Aug 2008 11:05:10 -0000 1.265 +++ src/backend/access/transam/xact.c 8 Oct 2008 01:53:44 -0000 @@ -47,6 +47,7 @@ #include "utils/memutils.h" #include "utils/relcache.h" #include "utils/snapmgr.h" +#include "utils/tqual.h" #include "utils/xml.h" #include "pg_trace.h" @@ -65,13 +66,6 @@ int CommitDelay = 0; /* precommit delay in microseconds */ int CommitSiblings = 5; /* # concurrent xacts needed to sleep */ -/* - * MyXactAccessedTempRel is set when a temporary relation is accessed. - * We don't allow PREPARE TRANSACTION in that case. (This is global - * so that it can be set from heapam.c.) - */ -bool MyXactAccessedTempRel = false; - /* * transaction states - transaction state from server perspective @@ -209,6 +203,9 @@ */ static MemoryContext TransactionAbortContext = NULL; +/* Hash table containing Oids of accessed temporary relations */ +HTAB *accessedTempRel; + /* * List of add-on start- and end-of-xact callbacks */ @@ -1511,7 +1508,6 @@ XactIsoLevel = DefaultXactIsoLevel; XactReadOnly = DefaultXactReadOnly; forceSyncCommit = false; - MyXactAccessedTempRel = false; /* * reinitialize within-transaction counters @@ -1777,6 +1773,36 @@ RESUME_INTERRUPTS(); } +/* ---------------- + * enlistRelationIdFor2PCChecks - enlist a relation in the list of + * resources to check at PREPARE COMMIT time if we are part of + * a 2PC transaction. The resource will be removed from the list + * if the table is dropped before commit. + * ---------------- + */ +void +enlistRelationIdFor2PCChecks(Oid relationId) +{ + /* + * Each time a temporary relation is accessed, it is added to the + * accessedTempRel list. PREPARE TRANSACTION will fail if any + * of the accessed relation is still valid (not dropped). (This is + * called from from heapam.c.) + */ + if (accessedTempRel == NULL) + { // Allocate the list on-demand + HASHCTL ctl; + + ctl.keysize = sizeof(Oid); + ctl.entrysize = sizeof(Oid); + accessedTempRel = hash_create("accessed temp tables", 4, &ctl, + HASH_ELEM); + } + + // Add to the hash list if missing + Oid *tid = hash_search(accessedTempRel, &relationId, HASH_ENTER, NULL); + *tid = relationId; +} /* * PrepareTransaction @@ -1853,14 +1879,45 @@ * We must check this after executing any ON COMMIT actions, because * they might still access a temp relation. * - * XXX In principle this could be relaxed to allow some useful special - * cases, such as a temp table created and dropped all within the - * transaction. That seems to require much more bookkeeping though. + * We only allow to proceed further if the accessed temp tables have + * been dropped before PREPARE COMMIT. */ - if (MyXactAccessedTempRel) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("cannot PREPARE a transaction that has operated on temporary tables"))); + if (accessedTempRel != NULL) + { + HASH_SEQ_STATUS status; + Oid* tempTableOid; + + /* Prevent further updates to the list as recommended in hash_seq_init doc. */ + hash_freeze(accessedTempRel); + hash_seq_init(&status, accessedTempRel); + while ((tempTableOid = (Oid *) hash_seq_search(&status)) != NULL) + { /* Check all accessed temp tables. If the table has been dropped, + * try_relation_open will fail and we can safely continue. */ + Relation tempTable = try_relation_open(*tempTableOid, NoLock); + if (tempTable != NULL) + { /* We have an open temp table at PREPARE COMMIT time. We + * will only accept empty temp tables and throw an error + * in other cases. */ + HeapScanDesc scan; + HeapTuple tuple; + scan = heap_beginscan(tempTable, SnapshotNow, 0, NULL); + if ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL) + { + hash_seq_term(&status); + hash_destroy(accessedTempRel); + accessedTempRel = NULL; + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("cannot PREPARE a transaction that has operated on temporary tables that arenot empty at commit time"))); + } + heap_endscan(scan); + relation_close(tempTable, NoLock); + } + } + hash_seq_term(&status); + hash_destroy(accessedTempRel); + accessedTempRel = NULL; + } /* Prevent cancel/die interrupt while cleaning up */ HOLD_INTERRUPTS(); @@ -2151,6 +2208,12 @@ elog(FATAL, "CleanupTransaction: unexpected state %s", TransStateAsString(s->state)); + if (accessedTempRel != NULL) + { + hash_destroy(accessedTempRel); + accessedTempRel = NULL; + } + /* * do abort cleanup processing */ Index: src/include/access/xact.h =================================================================== RCS file: /root/cvsrepo/pgsql/src/include/access/xact.h,v retrieving revision 1.95 diff -u -r1.95 xact.h --- src/include/access/xact.h 11 Aug 2008 11:05:11 -0000 1.95 +++ src/include/access/xact.h 8 Oct 2008 01:53:44 -0000 @@ -18,6 +18,7 @@ #include "nodes/pg_list.h" #include "storage/relfilenode.h" #include "utils/timestamp.h" +#include "postgres_ext.h" /* @@ -44,8 +45,8 @@ /* Asynchronous commits */ extern bool XactSyncCommit; -/* Kluge for 2PC support */ -extern bool MyXactAccessedTempRel; +/* List of temp tables accessed during a transaction for 2PC support */ +extern void enlistRelationIdFor2PCChecks(Oid relationId); /* * start- and end-of-transaction callbacks for dynamically loaded modules
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