From 745e6edaaeaccb92a2a5efe44b49c8bcc7d0ce01 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 12 Feb 2008 04:09:44 +0000 Subject: [PATCH] Fix SPI_cursor_open() and SPI_is_cursor_plan() to push the SPI stack before doing anything interesting, such as calling RevalidateCachedPlan(). The necessity of this is demonstrated by an example from Willem Buitendyk: during a replan, the planner might try to evaluate SPI-using functions, and so we'd better be in a clean SPI context. A small downside of this fix is that these two functions will now fail outright if called when not inside a SPI-using procedure (ie, a SPI_connect/SPI_finish pair). The documentation never promised or suggested that that would work, though; and they are normally used in concert with other functions, mainly SPI_prepare, that always have failed in such a case. So the odds of breaking something seem pretty low. In passing, make SPI_is_cursor_plan's error handling convention clearer, and fix documentation's erroneous claim that SPI_cursor_open would return NULL on error. Before 8.3 these functions could not invoke replanning, so there is probably no need for back-patching. --- doc/src/sgml/spi.sgml | 15 +++++++++------ src/backend/executor/spi.c | 20 +++++++++++++++++++- 2 files changed, 28 insertions(+), 7 deletions(-) diff --git a/doc/src/sgml/spi.sgml b/doc/src/sgml/spi.sgml index fca48caec0..d488c203d3 100644 --- a/doc/src/sgml/spi.sgml +++ b/doc/src/sgml/spi.sgml @@ -1,4 +1,4 @@ - + Server Programming Interface @@ -1077,9 +1077,12 @@ bool SPI_is_cursor_plan(SPIPlanPtr plan) Return Value true or false to indicate if the - plan can produce a cursor or not. - If the plan is NULL or invalid, - SPI_result is set to SPI_ERROR_ARGUMENT + plan can produce a cursor or not, with + SPI_result set to zero. + If it is not possible to determine the answer (for example, + if the plan is NULL or invalid, + or if called when not connected to SPI), then + SPI_result is set to a suitable error code and false is returned. @@ -1442,8 +1445,8 @@ Portal SPI_cursor_open(const char * name, SPIPlanPtr Return Value - pointer to portal containing the cursor, or NULL - on error + Pointer to portal containing the cursor. Note there is no error + return convention; any error will be reported via elog. diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c index ae083f7225..a23c4d017a 100644 --- a/src/backend/executor/spi.c +++ b/src/backend/executor/spi.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.187 2008/01/01 19:45:49 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.188 2008/02/12 04:09:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -886,6 +886,10 @@ SPI_cursor_open(const char *name, SPIPlanPtr plan, Assert(list_length(plan->plancache_list) == 1); plansource = (CachedPlanSource *) linitial(plan->plancache_list); + /* Push the SPI stack */ + if (_SPI_begin_call(false) < 0) + elog(ERROR, "SPI_cursor_open called while not connected"); + /* Reset SPI result (note we deliberately don't touch lastoid) */ SPI_processed = 0; SPI_tuptable = NULL; @@ -1041,6 +1045,9 @@ SPI_cursor_open(const char *name, SPIPlanPtr plan, Assert(portal->strategy != PORTAL_MULTI_QUERY); + /* Pop the SPI stack */ + _SPI_end_call(false); + /* Return the created portal */ return portal; } @@ -1180,9 +1187,17 @@ SPI_is_cursor_plan(SPIPlanPtr plan) } if (list_length(plan->plancache_list) != 1) + { + SPI_result = 0; return false; /* not exactly 1 pre-rewrite command */ + } plansource = (CachedPlanSource *) linitial(plan->plancache_list); + /* Need _SPI_begin_call in case replanning invokes SPI-using functions */ + SPI_result = _SPI_begin_call(false); + if (SPI_result < 0) + return false; + if (plan->saved) { /* Make sure the plan is up to date */ @@ -1190,6 +1205,9 @@ SPI_is_cursor_plan(SPIPlanPtr plan) ReleaseCachedPlan(cplan, true); } + _SPI_end_call(false); + SPI_result = 0; + /* Does it return tuples? */ if (plansource->resultDesc) return true; -- 2.40.0