diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtinsert.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtinsert.c | 81 |
1 files changed, 40 insertions, 41 deletions
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c index 7dbaa2c245f..5f7ecbe16da 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 1.159 2007/09/12 22:10:26 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.160 2007/09/20 17:56:30 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -193,8 +193,6 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel, */ for (;;) { - HeapTupleData htup; - Buffer hbuffer; ItemId curitemid; IndexTuple curitup; BlockNumber nblkno; @@ -223,6 +221,9 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel, */ if (!ItemIdIsDead(curitemid)) { + ItemPointerData htid; + bool all_dead; + /* * _bt_compare returns 0 for (1,NULL) and (1,NULL) - this's * how we handling NULLs - and so we must not use _bt_compare @@ -234,17 +235,20 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel, /* okay, we gotta fetch the heap tuple ... */ curitup = (IndexTuple) PageGetItem(page, curitemid); - htup.t_self = curitup->t_tid; - if (heap_fetch(heapRel, &SnapshotDirty, &htup, &hbuffer, - true, NULL)) + htid = curitup->t_tid; + + /* + * We check the whole HOT-chain to see if there is any tuple + * that satisfies SnapshotDirty. This is necessary because + * we have just a single index entry for the entire chain. + */ + if (heap_hot_search(&htid, heapRel, &SnapshotDirty, &all_dead)) { /* it is a duplicate */ TransactionId xwait = (TransactionIdIsValid(SnapshotDirty.xmin)) ? SnapshotDirty.xmin : SnapshotDirty.xmax; - ReleaseBuffer(hbuffer); - /* * If this tuple is being updated by other transaction * then we have to wait for its commit/abort. @@ -263,15 +267,22 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel, * is itself now committed dead --- if so, don't complain. * This is a waste of time in normal scenarios but we must * do it to support CREATE INDEX CONCURRENTLY. + * + * We must follow HOT-chains here because during + * concurrent index build, we insert the root TID though + * the actual tuple may be somewhere in the HOT-chain. + * While following the chain we might not stop at the exact + * tuple which triggered the insert, but that's OK because + * if we find a live tuple anywhere in this chain, we have + * a unique key conflict. The other live tuple is not part + * of this chain because it had a different index entry. */ - htup.t_self = itup->t_tid; - if (heap_fetch(heapRel, SnapshotSelf, &htup, &hbuffer, - false, NULL)) + htid = itup->t_tid; + if (heap_hot_search(&htid, heapRel, SnapshotSelf, NULL)) { /* Normal case --- it's still live */ - ReleaseBuffer(hbuffer); } - else if (htup.t_data != NULL) + else { /* * It's been deleted, so no error, and no need to @@ -279,39 +290,27 @@ _bt_check_unique(Relation rel, IndexTuple itup, Relation heapRel, */ break; } - else - { - /* couldn't find the tuple?? */ - elog(ERROR, "failed to fetch tuple being inserted"); - } ereport(ERROR, (errcode(ERRCODE_UNIQUE_VIOLATION), errmsg("duplicate key value violates unique constraint \"%s\"", RelationGetRelationName(rel)))); } - else if (htup.t_data != NULL) + else if (all_dead) { /* - * Hmm, if we can't see the tuple, maybe it can be marked - * killed. This logic should match index_getnext and - * btgettuple. + * The conflicting tuple (or whole HOT chain) is dead to + * everyone, so we may as well mark the index entry + * killed. */ - LockBuffer(hbuffer, BUFFER_LOCK_SHARE); - if (HeapTupleSatisfiesVacuum(htup.t_data, RecentGlobalXmin, - hbuffer) == HEAPTUPLE_DEAD) - { - ItemIdMarkDead(curitemid); - opaque->btpo_flags |= BTP_HAS_GARBAGE; - /* be sure to mark the proper buffer dirty... */ - if (nbuf != InvalidBuffer) - SetBufferCommitInfoNeedsSave(nbuf); - else - SetBufferCommitInfoNeedsSave(buf); - } - LockBuffer(hbuffer, BUFFER_LOCK_UNLOCK); + ItemIdMarkDead(curitemid); + opaque->btpo_flags |= BTP_HAS_GARBAGE; + /* be sure to mark the proper buffer dirty... */ + if (nbuf != InvalidBuffer) + SetBufferCommitInfoNeedsSave(nbuf); + else + SetBufferCommitInfoNeedsSave(buf); } - ReleaseBuffer(hbuffer); } } @@ -840,7 +839,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright, itemsz = ItemIdGetLength(itemid); item = (IndexTuple) PageGetItem(origpage, itemid); if (PageAddItem(rightpage, (Item) item, itemsz, rightoff, - false) == InvalidOffsetNumber) + false, false) == InvalidOffsetNumber) elog(PANIC, "failed to add hikey to the right sibling"); rightoff = OffsetNumberNext(rightoff); } @@ -865,7 +864,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright, item = (IndexTuple) PageGetItem(origpage, itemid); } if (PageAddItem(leftpage, (Item) item, itemsz, leftoff, - false) == InvalidOffsetNumber) + false, false) == InvalidOffsetNumber) elog(PANIC, "failed to add hikey to the left sibling"); leftoff = OffsetNumberNext(leftoff); @@ -1700,7 +1699,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf) * benefit of _bt_restore_page(). */ if (PageAddItem(rootpage, (Item) new_item, itemsz, P_HIKEY, - false) == InvalidOffsetNumber) + false, false) == InvalidOffsetNumber) elog(PANIC, "failed to add leftkey to new root page"); pfree(new_item); @@ -1718,7 +1717,7 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf) * insert the right page pointer into the new root page. */ if (PageAddItem(rootpage, (Item) new_item, itemsz, P_FIRSTKEY, - false) == InvalidOffsetNumber) + false, false) == InvalidOffsetNumber) elog(PANIC, "failed to add rightkey to new root page"); pfree(new_item); @@ -1805,7 +1804,7 @@ _bt_pgaddtup(Relation rel, } if (PageAddItem(page, (Item) itup, itemsize, itup_off, - false) == InvalidOffsetNumber) + false, false) == InvalidOffsetNumber) elog(PANIC, "failed to add item to the %s for \"%s\"", where, RelationGetRelationName(rel)); } |