diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtinsert.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtinsert.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c index ad6b632b2d..89f8810bde 100644 --- a/src/backend/access/nbtree/nbtinsert.c +++ b/src/backend/access/nbtree/nbtinsert.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.136 2006/04/25 22:46:05 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.137 2006/05/08 00:00:09 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -700,14 +700,18 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright, ropaque = (BTPageOpaque) PageGetSpecialPointer(rightpage); /* if we're splitting this page, it won't be the root when we're done */ + /* also, clear the SPLIT_END flag in both pages */ lopaque->btpo_flags = oopaque->btpo_flags; - lopaque->btpo_flags &= ~BTP_ROOT; + lopaque->btpo_flags &= ~(BTP_ROOT | BTP_SPLIT_END); ropaque->btpo_flags = lopaque->btpo_flags; lopaque->btpo_prev = oopaque->btpo_prev; lopaque->btpo_next = BufferGetBlockNumber(rbuf); ropaque->btpo_prev = BufferGetBlockNumber(buf); ropaque->btpo_next = oopaque->btpo_next; lopaque->btpo.level = ropaque->btpo.level = oopaque->btpo.level; + /* Since we already have write-lock on both pages, ok to read cycleid */ + lopaque->btpo_cycleid = _bt_vacuum_cycleid(rel); + ropaque->btpo_cycleid = lopaque->btpo_cycleid; /* * If the page we're splitting is not the rightmost page at its level in @@ -836,6 +840,21 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright, sopaque = (BTPageOpaque) PageGetSpecialPointer(spage); if (sopaque->btpo_prev != ropaque->btpo_prev) elog(PANIC, "right sibling's left-link doesn't match"); + /* + * Check to see if we can set the SPLIT_END flag in the right-hand + * split page; this can save some I/O for vacuum since it need not + * proceed to the right sibling. We can set the flag if the right + * sibling has a different cycleid: that means it could not be part + * of a group of pages that were all split off from the same ancestor + * page. If you're confused, imagine that page A splits to A B and + * then again, yielding A C B, while vacuum is in progress. Tuples + * originally in A could now be in either B or C, hence vacuum must + * examine both pages. But if D, our right sibling, has a different + * cycleid then it could not contain any tuples that were in A when + * the vacuum started. + */ + if (sopaque->btpo_cycleid != ropaque->btpo_cycleid) + ropaque->btpo_flags |= BTP_SPLIT_END; } /* @@ -1445,6 +1464,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf) rootopaque->btpo_flags = BTP_ROOT; rootopaque->btpo.level = ((BTPageOpaque) PageGetSpecialPointer(lpage))->btpo.level + 1; + rootopaque->btpo_cycleid = 0; /* update metapage data */ metad->btm_root = rootblknum; |