diff options
Diffstat (limited to 'src/backend/commands/vacuumlazy.c')
| -rw-r--r-- | src/backend/commands/vacuumlazy.c | 123 |
1 files changed, 48 insertions, 75 deletions
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c index c89dc20404c..b57ce14a700 100644 --- a/src/backend/commands/vacuumlazy.c +++ b/src/backend/commands/vacuumlazy.c @@ -36,7 +36,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.80 2006/10/04 00:29:52 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/vacuumlazy.c,v 1.81 2006/11/05 22:42:08 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -78,7 +78,6 @@ typedef struct LVRelStats double tuples_deleted; BlockNumber nonempty_pages; /* actually, last nonempty page + 1 */ Size threshold; /* minimum interesting free space */ - TransactionId minxid; /* minimum Xid present anywhere in table */ /* List of TIDs of tuples we intend to delete */ /* NB: this list is ordered by TID address */ int num_dead_tuples; /* current # of entries */ @@ -96,11 +95,13 @@ typedef struct LVRelStats static int elevel = -1; +static TransactionId OldestXmin; +static TransactionId FreezeLimit; + /* non-export function prototypes */ static void lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, - Relation *Irel, int nindexes, TransactionId FreezeLimit, - TransactionId OldestXmin); + Relation *Irel, int nindexes); static void lazy_vacuum_heap(Relation onerel, LVRelStats *vacrelstats); static void lazy_vacuum_index(Relation indrel, IndexBulkDeleteResult **stats, @@ -110,10 +111,9 @@ static void lazy_cleanup_index(Relation indrel, LVRelStats *vacrelstats); static int lazy_vacuum_page(Relation onerel, BlockNumber blkno, Buffer buffer, int tupindex, LVRelStats *vacrelstats); -static void lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats, - TransactionId OldestXmin); +static void lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats); static BlockNumber count_nondeletable_pages(Relation onerel, - LVRelStats *vacrelstats, TransactionId OldestXmin); + LVRelStats *vacrelstats); static void lazy_space_alloc(LVRelStats *vacrelstats, BlockNumber relblocks); static void lazy_record_dead_tuple(LVRelStats *vacrelstats, ItemPointer itemptr); @@ -129,8 +129,7 @@ static int vac_cmp_page_spaces(const void *left, const void *right); * lazy_vacuum_rel() -- perform LAZY VACUUM for one heap relation * * This routine vacuums a single heap, cleans out its indexes, and - * updates its relpages and reltuples statistics, as well as the - * relminxid and relvacuumxid information. + * updates its relpages and reltuples statistics. * * At entry, we have already established a transaction and opened * and locked the relation. @@ -142,8 +141,6 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt) Relation *Irel; int nindexes; BlockNumber possibly_freeable; - TransactionId OldestXmin, - FreezeLimit; if (vacstmt->verbose) elevel = INFO; @@ -159,23 +156,12 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt) /* XXX should we scale it up or down? Adjust vacuum.c too, if so */ vacrelstats->threshold = GetAvgFSMRequestSize(&onerel->rd_node); - /* - * Set initial minimum Xid, which will be updated if a smaller Xid is - * found in the relation by lazy_scan_heap. - * - * We use RecentXmin here (the minimum Xid that belongs to a transaction - * that is still open according to our snapshot), because it is the - * earliest transaction that could concurrently insert new tuples in the - * table. - */ - vacrelstats->minxid = RecentXmin; - /* Open all indexes of the relation */ vac_open_indexes(onerel, RowExclusiveLock, &nindexes, &Irel); vacrelstats->hasindex = (nindexes > 0); /* Do the vacuuming */ - lazy_scan_heap(onerel, vacrelstats, Irel, nindexes, FreezeLimit, OldestXmin); + lazy_scan_heap(onerel, vacrelstats, Irel, nindexes); /* Done with indexes */ vac_close_indexes(nindexes, Irel, NoLock); @@ -189,7 +175,7 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt) possibly_freeable = vacrelstats->rel_pages - vacrelstats->nonempty_pages; if (possibly_freeable >= REL_TRUNCATE_MINIMUM || possibly_freeable >= vacrelstats->rel_pages / REL_TRUNCATE_FRACTION) - lazy_truncate_heap(onerel, vacrelstats, OldestXmin); + lazy_truncate_heap(onerel, vacrelstats); /* Update shared free space map with final free space info */ lazy_update_fsm(onerel, vacrelstats); @@ -199,7 +185,7 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt) vacrelstats->rel_pages, vacrelstats->rel_tuples, vacrelstats->hasindex, - vacrelstats->minxid, OldestXmin); + FreezeLimit); /* report results to the stats collector, too */ pgstat_report_vacuum(RelationGetRelid(onerel), onerel->rd_rel->relisshared, @@ -215,16 +201,12 @@ lazy_vacuum_rel(Relation onerel, VacuumStmt *vacstmt) * of live tuples in the heap. When done, or when we run low on space * for dead-tuple TIDs, invoke vacuuming of indexes and heap. * - * It also updates the minimum Xid found anywhere on the table in - * vacrelstats->minxid, for later storing it in pg_class.relminxid. - * * If there are no indexes then we just vacuum each dirty page as we * process it, since there's no point in gathering many tuples. */ static void lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, - Relation *Irel, int nindexes, TransactionId FreezeLimit, - TransactionId OldestXmin) + Relation *Irel, int nindexes) { BlockNumber nblocks, blkno; @@ -266,10 +248,11 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, Page page; OffsetNumber offnum, maxoff; - bool pgchanged, - tupgone, + bool tupgone, hastup; int prev_dead_count; + OffsetNumber frozen[MaxOffsetNumber]; + int nfrozen; vacuum_delay_point(); @@ -293,7 +276,7 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, buf = ReadBuffer(onerel, blkno); - /* In this phase we only need shared access to the buffer */ + /* Initially, we only need shared access to the buffer */ LockBuffer(buf, BUFFER_LOCK_SHARE); page = BufferGetPage(buf); @@ -349,7 +332,7 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, continue; } - pgchanged = false; + nfrozen = 0; hastup = false; prev_dead_count = vacrelstats->num_dead_tuples; maxoff = PageGetMaxOffsetNumber(page); @@ -379,31 +362,7 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, tupgone = true; /* we can delete the tuple */ break; case HEAPTUPLE_LIVE: - - /* - * Tuple is good. Consider whether to replace its xmin - * value with FrozenTransactionId. - * - * NB: Since we hold only a shared buffer lock here, we - * are assuming that TransactionId read/write is atomic. - * This is not the only place that makes such an - * assumption. It'd be possible to avoid the assumption by - * momentarily acquiring exclusive lock, but for the - * moment I see no need to. - */ - if (TransactionIdIsNormal(HeapTupleHeaderGetXmin(tuple.t_data)) && - TransactionIdPrecedes(HeapTupleHeaderGetXmin(tuple.t_data), - FreezeLimit)) - { - HeapTupleHeaderSetXmin(tuple.t_data, FrozenTransactionId); - /* infomask should be okay already */ - Assert(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED); - pgchanged = true; - } - - /* - * Other checks... - */ + /* Tuple is good --- but let's do some validity checks */ if (onerel->rd_rel->relhasoids && !OidIsValid(HeapTupleGetOid(&tuple))) elog(WARNING, "relation \"%s\" TID %u/%u: OID is invalid", @@ -435,23 +394,41 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, } else { - TransactionId min; - num_tuples += 1; hastup = true; /* - * If the tuple is alive, we consider it for the "minxid" - * calculations. + * Each non-removable tuple must be checked to see if it + * needs freezing. If we already froze anything, then + * we've already switched the buffer lock to exclusive. */ - min = vactuple_get_minxid(&tuple); - if (TransactionIdIsValid(min) && - TransactionIdPrecedes(min, vacrelstats->minxid)) - vacrelstats->minxid = min; + if (heap_freeze_tuple(tuple.t_data, FreezeLimit, + (nfrozen > 0) ? InvalidBuffer : buf)) + frozen[nfrozen++] = offnum; } } /* scan along page */ /* + * If we froze any tuples, mark the buffer dirty, and write a WAL + * record recording the changes. We must log the changes to be + * crash-safe against future truncation of CLOG. + */ + if (nfrozen > 0) + { + MarkBufferDirty(buf); + /* no XLOG for temp tables, though */ + if (!onerel->rd_istemp) + { + XLogRecPtr recptr; + + recptr = log_heap_freeze(onerel, buf, FreezeLimit, + frozen, nfrozen); + PageSetLSN(page, recptr); + PageSetTLI(page, ThisTimeLineID); + } + } + + /* * If there are no indexes then we can vacuum the page right now * instead of doing a second scan. */ @@ -485,8 +462,6 @@ lazy_scan_heap(Relation onerel, LVRelStats *vacrelstats, if (hastup) vacrelstats->nonempty_pages = blkno + 1; - if (pgchanged) - MarkBufferDirty(buf); UnlockReleaseBuffer(buf); } @@ -710,7 +685,7 @@ lazy_cleanup_index(Relation indrel, vac_update_relstats(RelationGetRelid(indrel), stats->num_pages, stats->num_index_tuples, - false, InvalidTransactionId, InvalidTransactionId); + false, InvalidTransactionId); ereport(elevel, (errmsg("index \"%s\" now contains %.0f row versions in %u pages", @@ -731,8 +706,7 @@ lazy_cleanup_index(Relation indrel, * lazy_truncate_heap - try to truncate off any empty pages at the end */ static void -lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats, - TransactionId OldestXmin) +lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats) { BlockNumber old_rel_pages = vacrelstats->rel_pages; BlockNumber new_rel_pages; @@ -773,7 +747,7 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats, * because other backends could have added tuples to these pages whilst we * were vacuuming. */ - new_rel_pages = count_nondeletable_pages(onerel, vacrelstats, OldestXmin); + new_rel_pages = count_nondeletable_pages(onerel, vacrelstats); if (new_rel_pages >= old_rel_pages) { @@ -837,8 +811,7 @@ lazy_truncate_heap(Relation onerel, LVRelStats *vacrelstats, * Returns number of nondeletable pages (last nonempty page + 1). */ static BlockNumber -count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats, - TransactionId OldestXmin) +count_nondeletable_pages(Relation onerel, LVRelStats *vacrelstats) { BlockNumber blkno; HeapTupleData tuple; |