diff options
Diffstat (limited to 'src/backend/access/heap/vacuumlazy.c')
| -rw-r--r-- | src/backend/access/heap/vacuumlazy.c | 14 |
1 files changed, 7 insertions, 7 deletions
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); |