diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtree.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 54 |
1 files changed, 28 insertions, 26 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index b0acaf257f2..01899cfc166 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -12,7 +12,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.175 2010/02/08 04:33:53 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.176 2010/02/26 02:00:34 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -57,8 +57,8 @@ typedef struct IndexBulkDeleteCallback callback; void *callback_state; BTCycleId cycleid; - BlockNumber lastBlockVacuumed; /* last blkno reached by Vacuum scan */ - BlockNumber lastUsedPage; /* blkno of last non-recyclable page */ + BlockNumber lastBlockVacuumed; /* last blkno reached by Vacuum scan */ + BlockNumber lastUsedPage; /* blkno of last non-recyclable page */ BlockNumber totFreePages; /* true total # of free pages */ MemoryContext pagedelcontext; } BTVacState; @@ -630,7 +630,7 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, vstate.callback = callback; vstate.callback_state = callback_state; vstate.cycleid = cycleid; - vstate.lastBlockVacuumed = BTREE_METAPAGE; /* Initialise at first block */ + vstate.lastBlockVacuumed = BTREE_METAPAGE; /* Initialise at first block */ vstate.lastUsedPage = BTREE_METAPAGE; vstate.totFreePages = 0; @@ -702,8 +702,8 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, /* * We can't use _bt_getbuf() here because it always applies * _bt_checkpage(), which will barf on an all-zero page. We want to - * recycle all-zero pages, not fail. Also, we want to use a nondefault - * buffer access strategy. + * recycle all-zero pages, not fail. Also, we want to use a + * nondefault buffer access strategy. */ buf = ReadBufferExtended(rel, MAIN_FORKNUM, num_pages - 1, RBM_NORMAL, info->strategy); @@ -856,23 +856,25 @@ restart: htup = &(itup->t_tid); /* - * During Hot Standby we currently assume that XLOG_BTREE_VACUUM - * records do not produce conflicts. That is only true as long - * as the callback function depends only upon whether the index - * tuple refers to heap tuples removed in the initial heap scan. - * When vacuum starts it derives a value of OldestXmin. Backends - * taking later snapshots could have a RecentGlobalXmin with a - * later xid than the vacuum's OldestXmin, so it is possible that - * row versions deleted after OldestXmin could be marked as killed - * by other backends. The callback function *could* look at the - * index tuple state in isolation and decide to delete the index - * tuple, though currently it does not. If it ever did, we would - * need to reconsider whether XLOG_BTREE_VACUUM records should - * cause conflicts. If they did cause conflicts they would be - * fairly harsh conflicts, since we haven't yet worked out a way - * to pass a useful value for latestRemovedXid on the - * XLOG_BTREE_VACUUM records. This applies to *any* type of index - * that marks index tuples as killed. + * During Hot Standby we currently assume that + * XLOG_BTREE_VACUUM records do not produce conflicts. That is + * only true as long as the callback function depends only + * upon whether the index tuple refers to heap tuples removed + * in the initial heap scan. When vacuum starts it derives a + * value of OldestXmin. Backends taking later snapshots could + * have a RecentGlobalXmin with a later xid than the vacuum's + * OldestXmin, so it is possible that row versions deleted + * after OldestXmin could be marked as killed by other + * backends. The callback function *could* look at the index + * tuple state in isolation and decide to delete the index + * tuple, though currently it does not. If it ever did, we + * would need to reconsider whether XLOG_BTREE_VACUUM records + * should cause conflicts. If they did cause conflicts they + * would be fairly harsh conflicts, since we haven't yet + * worked out a way to pass a useful value for + * latestRemovedXid on the XLOG_BTREE_VACUUM records. This + * applies to *any* type of index that marks index tuples as + * killed. */ if (callback(htup, callback_state)) deletable[ndeletable++] = offnum; @@ -885,13 +887,13 @@ restart: */ if (ndeletable > 0) { - BlockNumber lastBlockVacuumed = BufferGetBlockNumber(buf); + BlockNumber lastBlockVacuumed = BufferGetBlockNumber(buf); _bt_delitems(rel, buf, deletable, ndeletable, true, vstate->lastBlockVacuumed); /* - * Keep track of the block number of the lastBlockVacuumed, so - * we can scan those blocks as well during WAL replay. This then + * Keep track of the block number of the lastBlockVacuumed, so we + * can scan those blocks as well during WAL replay. This then * provides concurrency protection and allows btrees to be used * while in recovery. */ |