diff options
Diffstat (limited to 'src/backend/commands/vacuum.c')
| -rw-r--r-- | src/backend/commands/vacuum.c | 47 |
1 files changed, 19 insertions, 28 deletions
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 7eb5777d3a..af7b6646d2 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(); /* |