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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2009-03-24 22:06:03 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2009-03-24 22:06:03 +0000 |
| commit | e5efda442cfcfa20a0cf6166952c671a0f39689b (patch) | |
| tree | 5b2463555c3b06d69511b0747c4bcb59c4309bb5 /src/backend/access/gin/gininsert.c | |
| parent | fc022d72c79b83dfe17aad33b6de2cf0a4f6f3ba (diff) | |
| download | postgresql-e5efda442cfcfa20a0cf6166952c671a0f39689b.tar.gz postgresql-e5efda442cfcfa20a0cf6166952c671a0f39689b.zip | |
Install a search tree depth limit in GIN bulk-insert operations, to prevent
them from degrading badly when the input is sorted or nearly so. In this
scenario the tree is unbalanced to the point of becoming a mere linked list,
so insertions become O(N^2). The easiest and most safely back-patchable
solution is to stop growing the tree sooner, ie limit the growth of N. We
might later consider a rebalancing tree algorithm, but it's not clear that
the benefit would be worth the cost and complexity. Per report from Sergey
Burladyan and an earlier complaint from Heikki.
Back-patch to 8.2; older versions didn't have GIN indexes.
Diffstat (limited to 'src/backend/access/gin/gininsert.c')
| -rw-r--r-- | src/backend/access/gin/gininsert.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c index d05882cdb94..f6a348eb85d 100644 --- a/src/backend/access/gin/gininsert.c +++ b/src/backend/access/gin/gininsert.c @@ -8,7 +8,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.19 2009/03/24 20:17:11 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.20 2009/03/24 22:06:03 tgl Exp $ *------------------------------------------------------------------------- */ @@ -245,7 +245,9 @@ ginBuildCallback(Relation index, HeapTuple htup, Datum *values, &htup->t_self); /* If we've maxed out our available memory, dump everything to the index */ - if (buildstate->accum.allocatedMemory >= maintenance_work_mem * 1024L) + /* Also dump if the tree seems to be getting too unbalanced */ + if (buildstate->accum.allocatedMemory >= maintenance_work_mem * 1024L || + buildstate->accum.maxdepth > GIN_MAX_TREE_DEPTH) { ItemPointerData *list; Datum entry; |