From: Tom Lane Date: Fri, 19 May 2006 16:31:05 +0000 (+0000) Subject: Fix nasty bug in nodeIndexscan.c's detection of duplicate tuples during X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=e350db4f7e06e43e52ccd2a7e046e2e4a587a058;p=users%2Fbernd%2Fpostgres.git Fix nasty bug in nodeIndexscan.c's detection of duplicate tuples during a multiple (OR'ed) indexscan. It was checking for duplicate tuple->t_data->t_ctid, when what it should be checking is tuple->t_self. The trouble situation occurs when a live tuple has t_ctid not pointing to itself, which can happen if an attempted UPDATE was rolled back. After a VACUUM, an unrelated tuple could be installed where the failed update tuple was, leading to one live tuple's t_ctid pointing to an unrelated tuple. If one of these tuples is fetched by an earlier OR'ed indexscan and the other by a later indexscan, nodeIndexscan.c would incorrectly ignore the second tuple. The bug exists in all 7.4.* and 8.0.* versions, but not in earlier or later branches because this code was only used in those releases. Per trouble report from Rafael Martinez Guerrero. --- diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c index a440cdf55f..f14b447703 100644 --- a/src/backend/executor/nodeIndexscan.c +++ b/src/backend/executor/nodeIndexscan.c @@ -219,7 +219,7 @@ IndexNext(IndexScanState *node) entry = (DupHashTabEntry *) hash_search(node->iss_DupHash, - &tuple->t_data->t_ctid, + &tuple->t_self, HASH_ENTER, &found); if (entry == NULL ||