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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2009-03-21 00:04:40 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2009-03-21 00:04:40 +0000 |
| commit | 596efd27edce20bba706f50de99a0f15bcc2a567 (patch) | |
| tree | 63c07c3c310e1b072f0a29a79220c81254dba3d8 /src/backend/nodes/copyfuncs.c | |
| parent | 249d936bed069877923f0369bd2ce51a6f8f925e (diff) | |
| download | postgresql-596efd27edce20bba706f50de99a0f15bcc2a567.tar.gz postgresql-596efd27edce20bba706f50de99a0f15bcc2a567.zip | |
Optimize multi-batch hash joins when the outer relation has a nonuniform
distribution, by creating a special fast path for the (first few) most common
values of the outer relation. Tuples having hashvalues matching the MCVs
are effectively forced to be in the first batch, so that we never write
them out to the batch temp files.
Bryce Cutt and Ramon Lawrence, with some editorialization by me.
Diffstat (limited to 'src/backend/nodes/copyfuncs.c')
| -rw-r--r-- | src/backend/nodes/copyfuncs.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c index 3c8bf6fb69a..f9a1efdc447 100644 --- a/src/backend/nodes/copyfuncs.c +++ b/src/backend/nodes/copyfuncs.c @@ -15,7 +15,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.426 2009/03/10 22:09:25 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.427 2009/03/21 00:04:39 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -735,6 +735,10 @@ _copyHash(Hash *from) /* * copy remainder of node */ + COPY_SCALAR_FIELD(skewTable); + COPY_SCALAR_FIELD(skewColumn); + COPY_SCALAR_FIELD(skewColType); + COPY_SCALAR_FIELD(skewColTypmod); return newnode; } |