Index: src/backend/access/heap/heapam.c =================================================================== RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/access/heap/heapam.c,v retrieving revision 1.249.2.2 diff -c -p -r1.249.2.2 heapam.c *** src/backend/access/heap/heapam.c 8 Mar 2008 21:58:07 -0000 1.249.2.2 --- src/backend/access/heap/heapam.c 10 Sep 2008 23:18:00 -0000 *************** heapgetpage(HeapScanDesc scan, BlockNumb *** 212,217 **** --- 212,218 ---- /* * Prune and repair fragmentation for the whole page, if possible. */ + Assert(TransactionIdIsValid(RecentGlobalXmin)); heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalXmin); /* *************** heap_hot_search_buffer(ItemPointer tid, *** 1488,1493 **** --- 1489,1496 ---- if (all_dead) *all_dead = true; + Assert(TransactionIdIsValid(RecentGlobalXmin)); + Assert(ItemPointerGetBlockNumber(tid) == BufferGetBlockNumber(buffer)); offnum = ItemPointerGetOffsetNumber(tid); at_chain_start = true; Index: src/backend/access/index/indexam.c =================================================================== RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/access/index/indexam.c,v retrieving revision 1.101 diff -c -p -r1.101 indexam.c *** src/backend/access/index/indexam.c 1 Jan 2008 19:45:46 -0000 1.101 --- src/backend/access/index/indexam.c 10 Sep 2008 23:18:00 -0000 *************** index_getnext(IndexScanDesc scan, ScanDi *** 419,424 **** --- 419,426 ---- SCAN_CHECKS; GET_SCAN_PROCEDURE(amgettuple); + Assert(TransactionIdIsValid(RecentGlobalXmin)); + /* * We always reset xs_hot_dead; if we are here then either we are just * starting the scan, or we previously returned a visible tuple, and in Index: src/backend/commands/vacuum.c =================================================================== RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/commands/vacuum.c,v retrieving revision 1.364.2.1 diff -c -p -r1.364.2.1 vacuum.c *** src/backend/commands/vacuum.c 14 Mar 2008 17:26:00 -0000 1.364.2.1 --- src/backend/commands/vacuum.c 10 Sep 2008 23:21:34 -0000 *************** vac_update_datfrozenxid(void) *** 781,794 **** bool dirty = false; /* ! * Initialize the "min" calculation with RecentGlobalXmin. Any ! * not-yet-committed pg_class entries for new tables must have ! * relfrozenxid at least this high, because any other open xact must have ! * RecentXmin >= its PGPROC.xmin >= our RecentGlobalXmin; see ! * AddNewRelationTuple(). So we cannot produce a wrong minimum by ! * starting with this. */ ! newFrozenXid = RecentGlobalXmin; /* * We must seqscan pg_class to find the minimum Xid, because there is no --- 781,792 ---- bool dirty = false; /* ! * Initialize the "min" calculation with GetOldestXmin, which is a ! * reasonable approximation to the minimum relfrozenxid for not-yet- ! * committed pg_class entries for new tables; see AddNewRelationTuple(). ! * Se we cannot produce a wrong minimum by starting with this. */ ! newFrozenXid = GetOldestXmin(true, true); /* * We must seqscan pg_class to find the minimum Xid, because there is no *************** vacuum_rel(Oid relid, VacuumStmt *vacstm *** 982,999 **** /* Begin a transaction for vacuuming this relation */ StartTransactionCommand(); ! if (vacstmt->full) ! { ! /* functions in indexes may want a snapshot set */ ! ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); ! } ! else { /* ! * During a lazy VACUUM we do not run any user-supplied functions, and ! * so it should be safe to not create a transaction snapshot. ! * ! * We can furthermore set the PROC_IN_VACUUM flag, which lets other * concurrent VACUUMs know that they can ignore this one while * determining their OldestXmin. (The reason we don't set it during a * full VACUUM is exactly that we may have to run user- defined --- 980,995 ---- /* Begin a transaction for vacuuming this relation */ StartTransactionCommand(); ! /* ! * Functions in indexes may want a snapshot set. Also, setting ! * a snapshot ensures that RecentGlobalXmin is kept truly recent. ! */ ! ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); ! ! if (!vacstmt->full) { /* ! * During a lazy VACUUM we can set the PROC_IN_VACUUM flag, which lets other * concurrent VACUUMs know that they can ignore this one while * determining their OldestXmin. (The reason we don't set it during a * full VACUUM is exactly that we may have to run user- defined Index: src/backend/executor/nodeBitmapHeapscan.c =================================================================== RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/executor/nodeBitmapHeapscan.c,v retrieving revision 1.22 diff -c -p -r1.22 nodeBitmapHeapscan.c *** src/backend/executor/nodeBitmapHeapscan.c 1 Jan 2008 19:45:49 -0000 1.22 --- src/backend/executor/nodeBitmapHeapscan.c 10 Sep 2008 23:22:26 -0000 *************** *** 36,41 **** --- 36,42 ---- #include "postgres.h" #include "access/heapam.h" + #include "access/transam.h" #include "executor/execdebug.h" #include "executor/nodeBitmapHeapscan.h" #include "pgstat.h" *************** bitgetpage(HeapScanDesc scan, TBMIterate *** 258,263 **** --- 259,265 ---- /* * Prune and repair fragmentation for the whole page, if possible. */ + Assert(TransactionIdIsValid(RecentGlobalXmin)); heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalXmin); /* Index: src/backend/utils/init/postinit.c =================================================================== RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/utils/init/postinit.c,v retrieving revision 1.180 diff -c -p -r1.180 postinit.c *** src/backend/utils/init/postinit.c 1 Jan 2008 19:45:53 -0000 1.180 --- src/backend/utils/init/postinit.c 10 Sep 2008 23:25:26 -0000 *************** *** 44,49 **** --- 44,50 ---- #include "utils/plancache.h" #include "utils/portal.h" #include "utils/relcache.h" + #include "utils/tqual.h" #include "utils/syscache.h" *************** InitPostgres(const char *in_dbname, Oid *** 457,466 **** on_shmem_exit(ShutdownPostgres, 0); /* ! * Start a new transaction here before first access to db */ if (!bootstrap) StartTransactionCommand(); /* * Now that we have a transaction, we can take locks. Take a writer's --- 458,472 ---- on_shmem_exit(ShutdownPostgres, 0); /* ! * Start a new transaction here before first access to db, and get a ! * snapshot. We don't have a use for the snapshot itself, but we're ! * interested in the secondary effect that it sets RecentGlobalXmin. */ if (!bootstrap) + { StartTransactionCommand(); + (void) GetTransactionSnapshot(); + } /* * Now that we have a transaction, we can take locks. Take a writer's Index: src/backend/utils/time/tqual.c =================================================================== RCS file: /home/alvherre/Code/cvs/pgsql/src/backend/utils/time/tqual.c,v retrieving revision 1.109 diff -c -p -r1.109 tqual.c *** src/backend/utils/time/tqual.c 1 Jan 2008 19:45:55 -0000 1.109 --- src/backend/utils/time/tqual.c 10 Sep 2008 23:22:59 -0000 *************** Snapshot ActiveSnapshot = NULL; *** 75,84 **** * These are updated by GetSnapshotData. We initialize them this way * for the convenience of TransactionIdIsInProgress: even in bootstrap * mode, we don't want it to say that BootstrapTransactionId is in progress. */ TransactionId TransactionXmin = FirstNormalTransactionId; TransactionId RecentXmin = FirstNormalTransactionId; ! TransactionId RecentGlobalXmin = FirstNormalTransactionId; /* local functions */ static bool XidInMVCCSnapshot(TransactionId xid, Snapshot snapshot); --- 75,88 ---- * These are updated by GetSnapshotData. We initialize them this way * for the convenience of TransactionIdIsInProgress: even in bootstrap * mode, we don't want it to say that BootstrapTransactionId is in progress. + * + * RecentGlobalXmin is initialized to InvalidTransactionId, to ensure that no + * one tries to use a stale value. Readers should ensure that it has been set + * to something else before using it. */ TransactionId TransactionXmin = FirstNormalTransactionId; TransactionId RecentXmin = FirstNormalTransactionId; ! TransactionId RecentGlobalXmin = InvalidTransactionId; /* local functions */ static bool XidInMVCCSnapshot(TransactionId xid, Snapshot snapshot);