diff options
| -rw-r--r-- | src/backend/access/heap/pruneheap.c | 23 | ||||
| -rw-r--r-- | src/backend/access/heap/vacuumlazy.c | 14 |
2 files changed, 29 insertions, 8 deletions
diff --git a/src/backend/access/heap/pruneheap.c b/src/backend/access/heap/pruneheap.c index 3cdfc5b7f1b..869d82ad667 100644 --- a/src/backend/access/heap/pruneheap.c +++ b/src/backend/access/heap/pruneheap.c @@ -325,6 +325,8 @@ heap_page_prune_opt(Relation relation, Buffer buffer) * * cutoffs contains the freeze cutoffs, established by VACUUM at the beginning * of vacuuming the relation. Required if HEAP_PRUNE_FREEZE option is set. + * cutoffs->OldestXmin is also used to determine if dead tuples are + * HEAPTUPLE_RECENTLY_DEAD or HEAPTUPLE_DEAD. * * presult contains output parameters needed by callers, such as the number of * tuples removed and the offsets of dead items on the page after pruning. @@ -922,8 +924,27 @@ heap_prune_satisfies_vacuum(PruneState *prstate, HeapTuple tup, Buffer buffer) if (res != HEAPTUPLE_RECENTLY_DEAD) return res; + /* + * For VACUUM, we must be sure to prune tuples with xmax older than + * OldestXmin -- a visibility cutoff determined at the beginning of + * vacuuming the relation. OldestXmin is used for freezing determination + * and we cannot freeze dead tuples' xmaxes. + */ + if (prstate->cutoffs && + TransactionIdIsValid(prstate->cutoffs->OldestXmin) && + NormalTransactionIdPrecedes(dead_after, prstate->cutoffs->OldestXmin)) + return HEAPTUPLE_DEAD; + + /* + * Determine whether or not the tuple is considered dead when compared + * with the provided GlobalVisState. On-access pruning does not provide + * VacuumCutoffs. And for vacuum, even if the tuple's xmax is not older + * than OldestXmin, GlobalVisTestIsRemovableXid() could find the row dead + * if the GlobalVisState has been updated since the beginning of vacuuming + * the relation. + */ if (GlobalVisTestIsRemovableXid(prstate->vistest, dead_after)) - res = HEAPTUPLE_DEAD; + return HEAPTUPLE_DEAD; return res; } diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index 3f88cf1e8ef..abb47ae5960 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -438,13 +438,13 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, * as an upper bound on the XIDs stored in the pages we'll actually scan * (NewRelfrozenXid tracking must never be allowed to miss unfrozen XIDs). * - * Next acquire vistest, a related cutoff that's used in pruning. We - * expect vistest will always make heap_page_prune_and_freeze() remove any - * deleted tuple whose xmax is < OldestXmin. lazy_scan_prune must never - * become confused about whether a tuple should be frozen or removed. (In - * the future we might want to teach lazy_scan_prune to recompute vistest - * from time to time, to increase the number of dead tuples it can prune - * away.) + * Next acquire vistest, a related cutoff that's used in pruning. We use + * vistest in combination with OldestXmin to ensure that + * heap_page_prune_and_freeze() always removes any deleted tuple whose + * xmax is < OldestXmin. lazy_scan_prune must never become confused about + * whether a tuple should be frozen or removed. (In the future we might + * want to teach lazy_scan_prune to recompute vistest from time to time, + * to increase the number of dead tuples it can prune away.) */ vacrel->aggressive = vacuum_get_cutoffs(rel, params, &vacrel->cutoffs); vacrel->rel_pages = orig_rel_pages = RelationGetNumberOfBlocks(rel); |