diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/access/nbtree/nbtpage.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/backend/access/nbtree/nbtpage.c b/src/backend/access/nbtree/nbtpage.c index 76069661d45..52a214ed974 100644 --- a/src/backend/access/nbtree/nbtpage.c +++ b/src/backend/access/nbtree/nbtpage.c @@ -1001,9 +1001,16 @@ _bt_delitems_vacuum(Relation rel, Buffer buf, /* * Mark the page as not containing any LP_DEAD items. This is not * certainly true (there might be some that have recently been marked, but - * weren't included in our target-item list), but it will almost always be - * true and it doesn't seem worth an additional page scan to check it. - * Remember that BTP_HAS_GARBAGE is only a hint anyway. + * weren't targeted by VACUUM's heap scan), but it will be true often + * enough. VACUUM does not delete items purely because they have their + * LP_DEAD bit set, since doing so would necessitate explicitly logging a + * latestRemovedXid cutoff (this is how _bt_delitems_delete works). + * + * The consequences of falsely unsetting BTP_HAS_GARBAGE should be fairly + * limited, since we never falsely unset an LP_DEAD bit. Workloads that + * are particularly dependent on LP_DEAD bits being set quickly will + * usually manage to set the BTP_HAS_GARBAGE flag before the page fills up + * again anyway. */ opaque->btpo_flags &= ~BTP_HAS_GARBAGE; |