From a5713ec427f15f2c63eaed14f2a16a952b7ddf06 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 17 Sep 2004 18:28:53 +0000 Subject: [PATCH] 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 where there were no inner tuples at all. Thanks to Xiaoyu Wang for finding a test case that exposed this long-standing bug. --- src/backend/executor/nodeHashjoin.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c index fbc55655714..53215be6e91 100644 --- a/src/backend/executor/nodeHashjoin.c +++ b/src/backend/executor/nodeHashjoin.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeHashjoin.c,v 1.64 2004/08/29 05:06:42 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeHashjoin.c,v 1.65 2004/09/17 18:28:53 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -603,12 +603,14 @@ ExecHashJoinNewBatch(HashJoinState *hjstate) } /* - * We can skip over any batches that are empty on either side. Release - * associated temp files right away. + * Normally we can skip over any batches that are empty on either side + * --- but for JOIN_LEFT, can only skip when left side is empty. + * Release associated temp files right away. */ while (newbatch <= nbatch && - (innerBatchSize[newbatch - 1] == 0L || - outerBatchSize[newbatch - 1] == 0L)) + (outerBatchSize[newbatch - 1] == 0L || + (innerBatchSize[newbatch - 1] == 0L && + hjstate->js.jointype != JOIN_LEFT))) { BufFileClose(hashtable->innerBatchFile[newbatch - 1]); hashtable->innerBatchFile[newbatch - 1] = NULL;