diff options
Diffstat (limited to 'src/backend/commands/vacuum.c')
| -rw-r--r-- | src/backend/commands/vacuum.c | 90 |
1 files changed, 49 insertions, 41 deletions
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index a7a557fb0fe..0d4984cde6a 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.177 2000/12/08 06:43:44 inoue Exp $ + * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.178 2000/12/22 00:51:53 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -61,7 +61,7 @@ static void vacuum_init(void); static void vacuum_shutdown(void); static void vac_vacuum(NameData *VacRelP, bool analyze, List *anal_cols2); static VRelList getrels(NameData *VacRelP); -static void vacuum_rel(Oid relid, bool is_toastrel); +static void vacuum_rel(Oid relid); static void scan_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages, VacPageList fraged_pages); static void repair_frag(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages, VacPageList fraged_pages, int nindices, Relation *Irel); static void vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacpagelist); @@ -239,7 +239,7 @@ vac_vacuum(NameData *VacRelP, bool analyze, List *anal_cols2) /* vacuum each heap relation */ for (cur = vrl; cur != (VRelList) NULL; cur = cur->vrl_next) { - vacuum_rel(cur->vrl_relid, false); + vacuum_rel(cur->vrl_relid); /* analyze separately so locking is minimized */ if (analyze) analyze_rel(cur->vrl_relid, anal_cols2, MESSAGE_LEVEL); @@ -308,7 +308,7 @@ getrels(NameData *VacRelP) if (rkind != RELKIND_RELATION) { - elog(NOTICE, "Vacuum: can not process indecies, views and certain system tables"); + elog(NOTICE, "Vacuum: can not process indices, views and certain system tables"); continue; } @@ -342,23 +342,25 @@ getrels(NameData *VacRelP) * vacuum_rel() -- vacuum one heap relation * * This routine vacuums a single heap, cleans out its indices, and - * updates its statistics num_pages and num_tuples statistics. + * updates its num_pages and num_tuples statistics. * * Doing one heap at a time incurs extra overhead, since we need to * check that the heap exists again just before we vacuum it. The * reason that we do this is so that vacuuming can be spread across * many small transactions. Otherwise, two-phase locking would require * us to lock the entire database during one pass of the vacuum cleaner. + * + * At entry and exit, we are not inside a transaction. */ static void -vacuum_rel(Oid relid, bool is_toastrel) +vacuum_rel(Oid relid) { Relation onerel; + LockRelId onerelid; VacPageListData vacuum_pages; /* List of pages to vacuum and/or clean - * indices */ + * indices */ VacPageListData fraged_pages; /* List of pages with space enough for - * re-using */ - VacPage *vacpage; + * re-using */ Relation *Irel; int32 nindices, i; @@ -366,8 +368,8 @@ vacuum_rel(Oid relid, bool is_toastrel) bool reindex = false; Oid toast_relid; - if (!is_toastrel) - StartTransactionCommand(); + /* Begin a transaction for vacuuming this relation */ + StartTransactionCommand(); /* * Check for user-requested abort. Note we want this to be inside a @@ -384,8 +386,7 @@ vacuum_rel(Oid relid, bool is_toastrel) ObjectIdGetDatum(relid), 0, 0, 0)) { - if (!is_toastrel) - CommitTransactionCommand(); + CommitTransactionCommand(); return; } @@ -403,13 +404,25 @@ vacuum_rel(Oid relid, bool is_toastrel) elog(NOTICE, "Skipping \"%s\" --- only table owner can VACUUM it", RelationGetRelationName(onerel)); heap_close(onerel, AccessExclusiveLock); - if (!is_toastrel) - CommitTransactionCommand(); + CommitTransactionCommand(); return; } /* - * Remember the relation'ss TOAST relation for later + * Get a session-level exclusive lock too. This will protect our + * exclusive access to the relation across multiple transactions, + * so that we can vacuum the relation's TOAST table (if any) secure + * in the knowledge that no one is diddling the parent relation. + * + * NOTE: this cannot block, even if someone else is waiting for access, + * because the lock manager knows that both lock requests are from the + * same process. + */ + onerelid = onerel->rd_lockInfo.lockRelId; + LockRelationForSession(&onerelid, AccessExclusiveLock); + + /* + * Remember the relation's TOAST relation for later */ toast_relid = onerel->rd_rel->reltoastrelid; @@ -500,21 +513,6 @@ vacuum_rel(Oid relid, bool is_toastrel) if (reindex) activate_indexes_of_a_table(relid, true); - /* - * ok - free vacuum_pages list of reaped pages - * - * Isn't this a waste of code? Upcoming commit should free memory, no? - */ - if (vacuum_pages.num_pages > 0) - { - vacpage = vacuum_pages.pagedesc; - for (i = 0; i < vacuum_pages.num_pages; i++, vacpage++) - pfree(*vacpage); - pfree(vacuum_pages.pagedesc); - if (fraged_pages.num_pages > 0) - pfree(fraged_pages.pagedesc); - } - /* all done with this class, but hold lock until commit */ heap_close(onerel, NoLock); @@ -524,18 +522,24 @@ vacuum_rel(Oid relid, bool is_toastrel) vacrelstats); /* + * Complete the transaction and free all temporary memory used. + */ + CommitTransactionCommand(); + + /* * If the relation has a secondary toast one, vacuum that too - * while we still hold the lock on the master table. We don't - * need to propagate "analyze" to it, because the toaster + * while we still hold the session lock on the master table. + * We don't need to propagate "analyze" to it, because the toaster * always uses hardcoded index access and statistics are * totally unimportant for toast relations */ if (toast_relid != InvalidOid) - vacuum_rel(toast_relid, true); + vacuum_rel(toast_relid); - /* next command frees attribute stats */ - if (!is_toastrel) - CommitTransactionCommand(); + /* + * Now release the session-level lock on the master table. + */ + UnlockRelationForSession(&onerelid, AccessExclusiveLock); } /* @@ -1786,9 +1790,13 @@ failed to add item with len = %lu to page %u (free space %lu, nusd %u, noff %u)" if (num_moved > 0) { /* - * We have to commit our tuple' movings before we'll truncate - * relation, but we shouldn't lose our locks. And so - quick hack: - * record status of current transaction as committed, and continue. + * We have to commit our tuple movings before we truncate the + * relation. Ideally we should do Commit/StartTransactionCommand + * here, relying on the session-level table lock to protect our + * exclusive access to the relation. However, that would require + * a lot of extra code to close and re-open the relation, indices, + * etc. For now, a quick hack: record status of current transaction + * as committed, and continue. */ RecordTransactionCommit(); } @@ -1852,7 +1860,7 @@ failed to add item with len = %lu to page %u (free space %lu, nusd %u, noff %u)" /* * Reflect the motion of system tuples to catalog cache here. */ - CommandCounterIncrement(); + CommandCounterIncrement(); if (Nvacpagelist.num_pages > 0) { |