From c604ed56e3f9d4c236e06b717a18d1a5baa27c88 Mon Sep 17 00:00:00 2001 From: Tom Lane <tgl@sss.pgh.pa.us> Date: Sun, 12 Dec 2004 20:17:06 +0000 Subject: [PATCH] PREPARE and EXPLAIN need to copy the source query just like we recently had to do in DECLARE CURSOR. AFAICS these are all the places affected. PREPARE case per example from Michael Fuhr, EXPLAIN case located by grepping for planner calls ... --- src/backend/commands/explain.c | 12 +++++++++++- src/backend/commands/prepare.c | 15 +++++++++++++-- 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index 34f6aa51f78..66e795d422d 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994-5, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.127 2004/09/30 17:42:42 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.128 2004/12/12 20:17:06 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -75,6 +75,16 @@ ExplainQuery(ExplainStmt *stmt, DestReceiver *dest) List *rewritten; ListCell *l; + /* + * Because the planner is not cool about not scribbling on its input, + * we make a preliminary copy of the source querytree. This prevents + * problems in the case that the EXPLAIN is in a portal or plpgsql + * function and is executed repeatedly. (See also the same hack in + * DECLARE CURSOR and PREPARE.) XXX the planner really shouldn't + * modify its input ... FIXME someday. + */ + query = copyObject(query); + /* prepare for projection of tuples */ tstate = begin_tup_output_tupdesc(dest, ExplainResultDesc(stmt)); diff --git a/src/backend/commands/prepare.c b/src/backend/commands/prepare.c index ae9366c5ee1..66fa15c37a3 100644 --- a/src/backend/commands/prepare.c +++ b/src/backend/commands/prepare.c @@ -10,7 +10,7 @@ * Copyright (c) 2002-2004, PostgreSQL Global Development Group * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.34 2004/12/03 21:26:31 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.35 2004/12/12 20:17:06 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -48,6 +48,7 @@ void PrepareQuery(PrepareStmt *stmt) { const char *commandTag; + Query *query; List *query_list, *plan_list; @@ -87,8 +88,18 @@ PrepareQuery(PrepareStmt *stmt) * the query. */ + /* + * Because the planner is not cool about not scribbling on its input, + * we make a preliminary copy of the source querytree. This prevents + * problems in the case that the PREPARE is in a portal or plpgsql + * function and is executed repeatedly. (See also the same hack in + * DECLARE CURSOR and EXPLAIN.) XXX the planner really shouldn't + * modify its input ... FIXME someday. + */ + query = copyObject(stmt->query); + /* Rewrite the query. The result could be 0, 1, or many queries. */ - query_list = QueryRewrite(stmt->query); + query_list = QueryRewrite(query); /* Generate plans for queries. Snapshot is already set. */ plan_list = pg_plan_queries(query_list, NULL, false); -- GitLab