diff options
| -rw-r--r-- | src/backend/access/heap/heapam.c | 5 | ||||
| -rw-r--r-- | src/backend/access/index/indexam.c | 4 | ||||
| -rw-r--r-- | src/backend/commands/vacuum.c | 47 | ||||
| -rw-r--r-- | src/backend/executor/nodeBitmapHeapscan.c | 4 | ||||
| -rw-r--r-- | src/backend/utils/init/postinit.c | 10 | ||||
| -rw-r--r-- | src/backend/utils/time/snapmgr.c | 8 |
6 files changed, 43 insertions, 35 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 6d3528323bf..eb9f8701ae1 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.262 2008/08/11 11:05:10 heikki Exp $ + * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.263 2008/09/11 14:01:09 alvherre Exp $ * * * INTERFACE ROUTINES @@ -219,6 +219,7 @@ heapgetpage(HeapScanDesc scan, BlockNumber page) /* * Prune and repair fragmentation for the whole page, if possible. */ + Assert(TransactionIdIsValid(RecentGlobalXmin)); heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalXmin); /* @@ -1469,6 +1470,8 @@ heap_hot_search_buffer(ItemPointer tid, Buffer buffer, Snapshot snapshot, if (all_dead) *all_dead = true; + Assert(TransactionIdIsValid(RecentGlobalXmin)); + Assert(ItemPointerGetBlockNumber(tid) == BufferGetBlockNumber(buffer)); offnum = ItemPointerGetOffsetNumber(tid); at_chain_start = true; diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c index 7d6028804a5..0c132d5fc09 100644 --- a/src/backend/access/index/indexam.c +++ b/src/backend/access/index/indexam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.109 2008/06/19 00:46:03 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.110 2008/09/11 14:01:09 alvherre Exp $ * * INTERFACE ROUTINES * index_open - open an index relation by relation OID @@ -419,6 +419,8 @@ index_getnext(IndexScanDesc scan, ScanDirection direction) 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 diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 7eb5777d3ab..af7b6646d28 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -13,7 +13,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.376 2008/08/13 00:07:50 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.377 2008/09/11 14:01:09 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -790,14 +790,12 @@ vac_update_datfrozenxid(void) 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. + * 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 = RecentGlobalXmin; + newFrozenXid = GetOldestXmin(true, true); /* * We must seqscan pg_class to find the minimum Xid, because there is no @@ -990,18 +988,16 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound) /* Begin a transaction for vacuuming this relation */ StartTransactionCommand(); - if (vacstmt->full) - { - /* functions in indexes may want a snapshot set */ - PushActiveSnapshot(GetTransactionSnapshot()); - } - else + /* + * Functions in indexes may want a snapshot set. Also, setting + * a snapshot ensures that RecentGlobalXmin is kept truly recent. + */ + PushActiveSnapshot(GetTransactionSnapshot()); + + if (!vacstmt->full) { /* - * 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 + * In 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 @@ -1050,8 +1046,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound) if (!onerel) { - if (vacstmt->full) - PopActiveSnapshot(); + PopActiveSnapshot(); CommitTransactionCommand(); return; } @@ -1082,8 +1077,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound) (errmsg("skipping \"%s\" --- only table or database owner can vacuum it", RelationGetRelationName(onerel)))); relation_close(onerel, lmode); - if (vacstmt->full) - PopActiveSnapshot(); + PopActiveSnapshot(); CommitTransactionCommand(); return; } @@ -1099,8 +1093,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound) (errmsg("skipping \"%s\" --- cannot vacuum indexes, views, or special system tables", RelationGetRelationName(onerel)))); relation_close(onerel, lmode); - if (vacstmt->full) - PopActiveSnapshot(); + PopActiveSnapshot(); CommitTransactionCommand(); return; } @@ -1115,8 +1108,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound) if (isOtherTempNamespace(RelationGetNamespace(onerel))) { relation_close(onerel, lmode); - if (vacstmt->full) - PopActiveSnapshot(); + PopActiveSnapshot(); CommitTransactionCommand(); return; } @@ -1168,8 +1160,7 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, bool do_toast, bool for_wraparound) /* * Complete the transaction and free all temporary memory used. */ - if (vacstmt->full) - PopActiveSnapshot(); + PopActiveSnapshot(); CommitTransactionCommand(); /* diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c index e09ece65375..41b9da62eab 100644 --- a/src/backend/executor/nodeBitmapHeapscan.c +++ b/src/backend/executor/nodeBitmapHeapscan.c @@ -21,7 +21,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.29 2008/06/19 00:46:04 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeBitmapHeapscan.c,v 1.30 2008/09/11 14:01:09 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -37,6 +37,7 @@ #include "access/heapam.h" #include "access/relscan.h" +#include "access/transam.h" #include "executor/execdebug.h" #include "executor/nodeBitmapHeapscan.h" #include "pgstat.h" @@ -262,6 +263,7 @@ bitgetpage(HeapScanDesc scan, TBMIterateResult *tbmres) /* * Prune and repair fragmentation for the whole page, if possible. */ + Assert(TransactionIdIsValid(RecentGlobalXmin)); heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalXmin); /* diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index e0dbbf93111..6b66b2e3926 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/init/postinit.c,v 1.184 2008/05/12 00:00:52 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/utils/init/postinit.c,v 1.185 2008/09/11 14:01:09 alvherre Exp $ * * *------------------------------------------------------------------------- @@ -47,6 +47,7 @@ #include "utils/plancache.h" #include "utils/portal.h" #include "utils/relcache.h" +#include "utils/snapmgr.h" #include "utils/syscache.h" #include "utils/tqual.h" @@ -461,10 +462,15 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username, on_shmem_exit(ShutdownPostgres, 0); /* - * Start a new transaction here before first access to db + * 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 diff --git a/src/backend/utils/time/snapmgr.c b/src/backend/utils/time/snapmgr.c index 841a92567d1..0add5f489c4 100644 --- a/src/backend/utils/time/snapmgr.c +++ b/src/backend/utils/time/snapmgr.c @@ -22,7 +22,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/time/snapmgr.c,v 1.4 2008/07/11 02:10:14 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/utils/time/snapmgr.c,v 1.5 2008/09/11 14:01:10 alvherre Exp $ * *------------------------------------------------------------------------- */ @@ -59,10 +59,14 @@ static Snapshot SecondarySnapshot = NULL; * 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 = FirstNormalTransactionId; +TransactionId RecentGlobalXmin = InvalidTransactionId; /* * Elements of the list of registered snapshots. |