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Commitf4d5c52

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Hashed LEFT JOIN would miss outer tuples with no inner match if the join
was large enough to be batched and the tuples fell into a batch wherethere were no inner tuples at all. Thanks to Xiaoyu Wang for finding atest case that exposed this long-standing bug.
1 parent3c06653 commitf4d5c52

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‎src/backend/executor/nodeHashjoin.c

Lines changed: 7 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeHashjoin.c,v 1.38 2001/03/22 06:16:13 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeHashjoin.c,v 1.38.2.1 2004/09/17 18:29:54 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
@@ -575,12 +575,14 @@ ExecHashJoinNewBatch(HashJoinState *hjstate)
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}
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/*
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* We can skip over any batches that are empty on either side. Release
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* associated temp files right away.
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* Normally we can skip over any batches that are empty on either side
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* --- but for JOIN_LEFT, can only skip when left side is empty.
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* Release associated temp files right away.
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*/
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while (newbatch <=nbatch&&
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(innerBatchSize[newbatch-1]==0L||
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outerBatchSize[newbatch-1]==0L))
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(outerBatchSize[newbatch-1]==0L||
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(innerBatchSize[newbatch-1]==0L&&
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hjstate->js.jointype!=JOIN_LEFT)))
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{
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BufFileClose(hashtable->innerBatchFile[newbatch-1]);
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hashtable->innerBatchFile[newbatch-1]=NULL;

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