diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtree.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index c02c4e7710d..9282c9ea22f 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -859,9 +859,13 @@ btvacuumcleanup(IndexVacuumInfo *info, IndexBulkDeleteResult *stats) * Maintain num_delpages value in metapage for _bt_vacuum_needs_cleanup(). * * num_delpages is the number of deleted pages now in the index that were - * not safe to place in the FSM to be recycled just yet. We expect that - * it will almost certainly be possible to place all of these pages in the - * FSM during the next VACUUM operation. + * not safe to place in the FSM to be recycled just yet. num_delpages is + * greater than 0 only when _bt_pagedel() actually deleted pages during + * our call to btvacuumscan(). Even then, _bt_pendingfsm_finalize() must + * have failed to place any newly deleted pages in the FSM just moments + * ago. (Actually, there are edge cases where recycling of the current + * VACUUM's newly deleted pages does not even become safe by the time the + * next VACUUM comes around. See nbtree/README.) */ Assert(stats->pages_deleted >= stats->pages_free); num_delpages = stats->pages_deleted - stats->pages_free; @@ -937,6 +941,14 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, "_bt_pagedel", ALLOCSET_DEFAULT_SIZES); + /* Initialize vstate fields used by _bt_pendingfsm_finalize */ + vstate.bufsize = 0; + vstate.maxbufsize = 0; + vstate.pendingpages = NULL; + vstate.npendingpages = 0; + /* Consider applying _bt_pendingfsm_finalize optimization */ + _bt_pendingfsm_init(rel, &vstate, (callback == NULL)); + /* * The outer loop iterates over all index pages except the metapage, in * physical order (we hope the kernel will cooperate in providing @@ -995,17 +1007,15 @@ btvacuumscan(IndexVacuumInfo *info, IndexBulkDeleteResult *stats, MemoryContextDelete(vstate.pagedelcontext); /* - * If we found any recyclable pages (and recorded them in the FSM), then - * forcibly update the upper-level FSM pages to ensure that searchers can - * find them. It's possible that the pages were also found during - * previous scans and so this is a waste of time, but it's cheap enough - * relative to scanning the index that it shouldn't matter much, and - * making sure that free pages are available sooner not later seems - * worthwhile. + * If there were any calls to _bt_pagedel() during scan of the index then + * see if any of the resulting pages can be placed in the FSM now. When + * it's not safe we'll have to leave it up to a future VACUUM operation. * - * Note that if no recyclable pages exist, we don't bother vacuuming the - * FSM at all. + * Finally, if we placed any pages in the FSM (either just now or during + * the scan), forcibly update the upper-level FSM pages to ensure that + * searchers can find them. */ + _bt_pendingfsm_finalize(rel, &vstate); if (stats->pages_free > 0) IndexFreeSpaceMapVacuum(rel); } |