From 17903a73759a1fa8266d44c1147a08f387581c0c Mon Sep 17 00:00:00 2001 From: Joe Conway Date: Tue, 3 Jan 2006 23:46:32 +0000 Subject: [PATCH] When the remote query result has a different number of columns than the local query specifies (e.g. in the FROM clause), throw an ERROR (instead of crashing). Fix for bug #2129 reported by Akio Iwaasa. --- contrib/dblink/README.dblink | 2 +- contrib/dblink/dblink.c | 48 +++++++++++++++++++++++------------- contrib/dblink/dblink.h | 2 +- contrib/dblink/doc/cursor | 7 ++++++ 4 files changed, 40 insertions(+), 19 deletions(-) diff --git a/contrib/dblink/README.dblink b/contrib/dblink/README.dblink index 22db3504913..9e1bdba6cba 100644 --- a/contrib/dblink/README.dblink +++ b/contrib/dblink/README.dblink @@ -8,7 +8,7 @@ * Darko Prenosil * Shridhar Daithankar * - * Copyright (c) 2001-2005, PostgreSQL Global Development Group + * Copyright (c) 2001-2006, PostgreSQL Global Development Group * ALL RIGHTS RESERVED; * * Permission to use, copy, modify, and distribute this software and its diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c index 35641c2e21e..7e98987dad8 100644 --- a/contrib/dblink/dblink.c +++ b/contrib/dblink/dblink.c @@ -8,7 +8,7 @@ * Darko Prenosil * Shridhar Daithankar * - * Copyright (c) 2001-2005, PostgreSQL Global Development Group + * Copyright (c) 2001-2006, PostgreSQL Global Development Group * ALL RIGHTS RESERVED; * * Permission to use, copy, modify, and distribute this software and its @@ -578,14 +578,6 @@ dblink_fetch(PG_FUNCTION_ARGS) /* got results, keep track of them */ funcctx->user_fctx = res; - /* fast track when no results */ - if (funcctx->max_calls < 1) - { - if (res) - PQclear(res); - SRF_RETURN_DONE(funcctx); - } - /* get a tuple descriptor for our result type */ switch (get_call_result_type(fcinfo, NULL, &tupdesc)) { @@ -608,6 +600,21 @@ dblink_fetch(PG_FUNCTION_ARGS) /* make sure we have a persistent copy of the tupdesc */ tupdesc = CreateTupleDescCopy(tupdesc); + /* check result and tuple descriptor have the same number of columns */ + if (PQnfields(res) != tupdesc->natts) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("remote query result rowtype does not match " + "the specified FROM clause rowtype"))); + + /* fast track when no results */ + if (funcctx->max_calls < 1) + { + if (res) + PQclear(res); + SRF_RETURN_DONE(funcctx); + } + /* store needed metadata for subsequent calls */ attinmeta = TupleDescGetAttInMetadata(tupdesc); funcctx->attinmeta = attinmeta; @@ -777,14 +784,6 @@ dblink_record(PG_FUNCTION_ARGS) if (freeconn) PQfinish(conn); - /* fast track when no results */ - if (funcctx->max_calls < 1) - { - if (res) - PQclear(res); - SRF_RETURN_DONE(funcctx); - } - if (!is_sql_cmd) { /* get a tuple descriptor for our result type */ @@ -810,6 +809,21 @@ dblink_record(PG_FUNCTION_ARGS) tupdesc = CreateTupleDescCopy(tupdesc); } + /* check result and tuple descriptor have the same number of columns */ + if (PQnfields(res) != tupdesc->natts) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("remote query result rowtype does not match " + "the specified FROM clause rowtype"))); + + /* fast track when no results */ + if (funcctx->max_calls < 1) + { + if (res) + PQclear(res); + SRF_RETURN_DONE(funcctx); + } + /* store needed metadata for subsequent calls */ attinmeta = TupleDescGetAttInMetadata(tupdesc); funcctx->attinmeta = attinmeta; diff --git a/contrib/dblink/dblink.h b/contrib/dblink/dblink.h index 63d6d525db9..8f2c9ff4c1f 100644 --- a/contrib/dblink/dblink.h +++ b/contrib/dblink/dblink.h @@ -8,7 +8,7 @@ * Darko Prenosil * Shridhar Daithankar * - * Copyright (c) 2001-2005, PostgreSQL Global Development Group + * Copyright (c) 2001-2006, PostgreSQL Global Development Group * ALL RIGHTS RESERVED; * * Permission to use, copy, modify, and distribute this software and its diff --git a/contrib/dblink/doc/cursor b/contrib/dblink/doc/cursor index b989fcb69cc..321c823e211 100644 --- a/contrib/dblink/doc/cursor +++ b/contrib/dblink/doc/cursor @@ -92,6 +92,13 @@ Outputs Returns setof record +Note + + On a mismatch between the number of return fields as specified in the FROM + clause, and the actual number of fields returned by the remote cursor, an + ERROR will be thrown. In this event, the remote cursor is still advanced + by as many rows as it would have been if the ERROR had not occurred. + Example usage test=# select dblink_connect('dbname=postgres');