Make use of plancache module for SPI plans. In particular, since plpgsql

uses SPI plans, this finally fixes the ancient gotcha that you can't
drop and recreate a temp table used by a plpgsql function.

Along the way, clean up SPI's API a little bit by declaring SPI plan
pointers as "SPIPlanPtr" instead of "void *".  This is cosmetic but
helps to forestall simple programming mistakes.  (I have changed some
but not all of the callers to match; there are still some "void *"'s
in contrib and the PL's.  This is intentional so that we can see if
anyone's compiler complains about it.)

4 files changed, 48 insertions, 50 deletions

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 4ba2bb7a98f..72200ced9dc 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -8,16 +8,14 @@
  *	across query and transaction boundaries, in fact they live as long as
  *	the backend does.  This works because the hashtable structures
  *	themselves are allocated by dynahash.c in its permanent DynaHashCxt,
- *	and the parse/plan node trees they point to are copied into
- *	TopMemoryContext using SPI_saveplan().	This is pretty ugly, since there
- *	is no way to free a no-longer-needed plan tree, but then again we don't
- *	yet have any bookkeeping that would allow us to detect that a plan isn't
- *	needed anymore.  Improve it someday.
+ *	and the SPI plans they point to are saved using SPI_saveplan().
+ *	There is not currently any provision for throwing away a no-longer-needed
+ *	plan --- consider improving this someday.
  *
  *
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.91 2007/02/14 01:58:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/ri_triggers.c,v 1.92 2007/03/15 23:12:06 tgl Exp $
  *
  * ----------
  */
@@ -35,7 +33,7 @@
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_operator.h"
 #include "commands/trigger.h"
-#include "executor/spi_priv.h"
+#include "executor/spi.h"
 #include "parser/parse_coerce.h"
 #include "parser/parse_relation.h"
 #include "miscadmin.h"
@@ -135,7 +133,7 @@ typedef struct RI_QueryKey
 typedef struct RI_QueryHashEntry
 {
 	RI_QueryKey key;
-	void	   *plan;
+	SPIPlanPtr	plan;
 } RI_QueryHashEntry;
 
 
@@ -206,18 +204,18 @@ static bool ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
 				  const RI_ConstraintInfo *riinfo);
 
 static void ri_InitHashTables(void);
-static void *ri_FetchPreparedPlan(RI_QueryKey *key);
-static void ri_HashPreparedPlan(RI_QueryKey *key, void *plan);
+static SPIPlanPtr ri_FetchPreparedPlan(RI_QueryKey *key);
+static void ri_HashPreparedPlan(RI_QueryKey *key, SPIPlanPtr plan);
 static RI_CompareHashEntry *ri_HashCompareOp(Oid eq_opr, Oid typeid);
 
 static void ri_CheckTrigger(FunctionCallInfo fcinfo, const char *funcname,
 				int tgkind);
 static void ri_FetchConstraintInfo(RI_ConstraintInfo *riinfo,
 					   Trigger *trigger, Relation trig_rel, bool rel_is_pk);
-static void *ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
+static SPIPlanPtr ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
 			 RI_QueryKey *qkey, Relation fk_rel, Relation pk_rel,
 			 bool cache_plan);
-static bool ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
+static bool ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
 				Relation fk_rel, Relation pk_rel,
 				HeapTuple old_tuple, HeapTuple new_tuple,
 				bool detectNewRows,
@@ -248,7 +246,7 @@ RI_FKey_check(PG_FUNCTION_ARGS)
 	HeapTuple	old_row;
 	Buffer		new_row_buf;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -542,7 +540,7 @@ ri_Check_Pk_Match(Relation pk_rel, Relation fk_rel,
 				  HeapTuple old_row,
 				  const RI_ConstraintInfo *riinfo)
 {
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	RI_QueryKey qkey;
 	int			i;
 	bool		result;
@@ -678,7 +676,7 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
 	Relation	pk_rel;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -855,7 +853,7 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
 	HeapTuple	new_row;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -1040,7 +1038,7 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
 	Relation	pk_rel;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -1203,7 +1201,7 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 	HeapTuple	new_row;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 	int			j;
 
@@ -1397,7 +1395,7 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
 	Relation	pk_rel;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -1569,7 +1567,7 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
 	HeapTuple	new_row;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -1744,7 +1742,7 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
 	Relation	pk_rel;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 
 	/*
@@ -1916,7 +1914,7 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
 	HeapTuple	new_row;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	int			i;
 	bool		use_cached_query;
 
@@ -2130,7 +2128,7 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
 	Relation	pk_rel;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 
 	/*
 	 * Check that this is a valid trigger call on the right time and event.
@@ -2313,7 +2311,7 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
 	HeapTuple	new_row;
 	HeapTuple	old_row;
 	RI_QueryKey qkey;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 
 	/*
 	 * Check that this is a valid trigger call on the right time and event.
@@ -2637,7 +2635,7 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 	int			old_work_mem;
 	char		workmembuf[32];
 	int			spi_result;
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 
 	/*
 	 * Check to make sure current user has enough permissions to do the test
@@ -3165,12 +3163,12 @@ ri_FetchConstraintInfo(RI_ConstraintInfo *riinfo,
  * If cache_plan is true, the plan is saved into our plan hashtable
  * so that we don't need to plan it again.
  */
-static void *
+static SPIPlanPtr
 ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
 			 RI_QueryKey *qkey, Relation fk_rel, Relation pk_rel,
 			 bool cache_plan)
 {
-	void	   *qplan;
+	SPIPlanPtr	qplan;
 	Relation	query_rel;
 	Oid			save_uid;
 
@@ -3212,7 +3210,7 @@ ri_PlanCheck(const char *querystr, int nargs, Oid *argtypes,
  * Perform a query to enforce an RI restriction
  */
 static bool
-ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
+ri_PerformCheck(RI_QueryKey *qkey, SPIPlanPtr qplan,
 				Relation fk_rel, Relation pk_rel,
 				HeapTuple old_tuple, HeapTuple new_tuple,
 				bool detectNewRows,
@@ -3576,7 +3574,7 @@ ri_InitHashTables(void)
  *	and saved SPI execution plans. Return the plan if found or NULL.
  * ----------
  */
-static void *
+static SPIPlanPtr
 ri_FetchPreparedPlan(RI_QueryKey *key)
 {
 	RI_QueryHashEntry *entry;
@@ -3606,7 +3604,7 @@ ri_FetchPreparedPlan(RI_QueryKey *key)
  * ----------
  */
 static void
-ri_HashPreparedPlan(RI_QueryKey *key, void *plan)
+ri_HashPreparedPlan(RI_QueryKey *key, SPIPlanPtr plan)
 {
 	RI_QueryHashEntry *entry;
 	bool		found;
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index f17061738a4..9ec0aa56f0a 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.252 2007/02/27 23:48:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.253 2007/03/15 23:12:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -105,9 +105,9 @@ typedef struct
  * Global data
  * ----------
  */
-static void *plan_getrulebyoid = NULL;
+static SPIPlanPtr plan_getrulebyoid = NULL;
 static char *query_getrulebyoid = "SELECT * FROM pg_catalog.pg_rewrite WHERE oid = $1";
-static void *plan_getviewrule = NULL;
+static SPIPlanPtr plan_getviewrule = NULL;
 static char *query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_class = $1 AND rulename = $2";
 
 
@@ -250,7 +250,7 @@ pg_get_ruledef_worker(Oid ruleoid, int prettyFlags)
 	if (plan_getrulebyoid == NULL)
 	{
 		Oid			argtypes[1];
-		void	   *plan;
+		SPIPlanPtr	plan;
 
 		argtypes[0] = OIDOID;
 		plan = SPI_prepare(query_getrulebyoid, 1, argtypes);
@@ -380,7 +380,7 @@ pg_get_viewdef_worker(Oid viewoid, int prettyFlags)
 	if (plan_getviewrule == NULL)
 	{
 		Oid			argtypes[2];
-		void	   *plan;
+		SPIPlanPtr	plan;
 
 		argtypes[0] = OIDOID;
 		argtypes[1] = NAMEOID;
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 921fe1d9f50..fa82837fd0c 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.34 2007/03/03 19:32:55 neilc Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/xml.c,v 1.35 2007/03/15 23:12:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1800,7 +1800,7 @@ query_to_xmlschema(PG_FUNCTION_ARGS)
 	const char *targetns = _textout(PG_GETARG_TEXT_P(3));
 
 	const char *result;
-	void	   *plan;
+	SPIPlanPtr	plan;
 	Portal		portal;
 
 	SPI_connect();
@@ -1871,7 +1871,7 @@ query_to_xml_and_xmlschema(PG_FUNCTION_ARGS)
 	const char *targetns = _textout(PG_GETARG_TEXT_P(3));
 
 	const char *xmlschema;
-	void	   *plan;
+	SPIPlanPtr	plan;
 	Portal		portal;
 
 	SPI_connect();
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index 95ed49818cb..61a576d35d9 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -33,7 +33,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.1 2007/03/13 00:33:42 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.2 2007/03/15 23:12:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -77,7 +77,6 @@ static void ScanQueryForRelids(Query *parsetree,
 							   void *arg);
 static bool ScanQueryWalker(Node *node, ScanQueryWalkerContext *context);
 static bool rowmark_member(List *rowMarks, int rt_index);
-static TupleDesc ComputeResultDesc(List *stmt_list);
 static void PlanCacheCallback(Datum arg, Oid relid);
 static void InvalRelid(Oid relid, LOCKMODE lockmode,
 					   InvalRelidContext *context);
@@ -153,7 +152,7 @@ CreateCachedPlan(Node *raw_parse_tree,
 	plansource->fully_planned = fully_planned;
 	plansource->fixed_result = fixed_result;
 	plansource->generation = 0;			/* StoreCachedPlan will increment */
-	plansource->resultDesc = ComputeResultDesc(stmt_list);
+	plansource->resultDesc = PlanCacheComputeResultDesc(stmt_list);
 	plansource->plan = NULL;
 	plansource->context = source_context;
 	plansource->orig_plan = NULL;
@@ -225,7 +224,7 @@ FastCreateCachedPlan(Node *raw_parse_tree,
 	plansource->fully_planned = fully_planned;
 	plansource->fixed_result = fixed_result;
 	plansource->generation = 0;			/* StoreCachedPlan will increment */
-	plansource->resultDesc = ComputeResultDesc(stmt_list);
+	plansource->resultDesc = PlanCacheComputeResultDesc(stmt_list);
 	plansource->plan = NULL;
 	plansource->context = context;
 	plansource->orig_plan = NULL;
@@ -271,12 +270,13 @@ StoreCachedPlan(CachedPlanSource *plansource,
 	{
 		/*
 		 * Make a dedicated memory context for the CachedPlan and its
-		 * subsidiary data.
+		 * subsidiary data.  It's probably not going to be large, but
+		 * just in case, use the default maxsize parameter.
 		 */
 		plan_context = AllocSetContextCreate(CacheMemoryContext,
 											 "CachedPlan",
-											 ALLOCSET_DEFAULT_MINSIZE,
-											 ALLOCSET_DEFAULT_INITSIZE,
+											 ALLOCSET_SMALL_MINSIZE,
+											 ALLOCSET_SMALL_INITSIZE,
 											 ALLOCSET_DEFAULT_MAXSIZE);
 
 		/*
@@ -445,7 +445,7 @@ RevalidateCachedPlan(CachedPlanSource *plansource, bool useResOwner)
 		 * Check or update the result tupdesc.  XXX should we use a weaker
 		 * condition than equalTupleDescs() here?
 		 */
-		resultDesc = ComputeResultDesc(slist);
+		resultDesc = PlanCacheComputeResultDesc(slist);
 		if (resultDesc == NULL && plansource->resultDesc == NULL)
 		{
 			/* OK, doesn't return tuples */
@@ -718,14 +718,14 @@ rowmark_member(List *rowMarks, int rt_index)
 }
 
 /*
- * ComputeResultDesc: given a list of either fully-planned statements or
- * Queries, determine the result tupledesc it will produce.  Returns NULL
+ * PlanCacheComputeResultDesc: given a list of either fully-planned statements
+ * or Queries, determine the result tupledesc it will produce.  Returns NULL
  * if the execution will not return tuples.
  *
  * Note: the result is created or copied into current memory context.
  */
-static TupleDesc
-ComputeResultDesc(List *stmt_list)
+TupleDesc
+PlanCacheComputeResultDesc(List *stmt_list)
 {
 	Node	   *node;
 	Query	   *query;