1 files changed, 128 insertions, 16 deletions

diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 9b167af6608..3da2d263023 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -49,8 +49,9 @@ static int	_SPI_curid = -1;
 static Portal SPI_cursor_open_internal(const char *name, SPIPlanPtr plan,
 						 ParamListInfo paramLI, bool read_only);
 
-static void _SPI_prepare_plan(const char *src, SPIPlanPtr plan,
-				  ParamListInfo boundParams);
+static void _SPI_prepare_plan(const char *src, SPIPlanPtr plan);
+
+static void _SPI_prepare_oneshot_plan(const char *src, SPIPlanPtr plan);
 
 static int _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 				  Snapshot snapshot, Snapshot crosscheck_snapshot,
@@ -355,7 +356,7 @@ SPI_execute(const char *src, bool read_only, long tcount)
 	plan.magic = _SPI_PLAN_MAGIC;
 	plan.cursor_options = 0;
 
-	_SPI_prepare_plan(src, &plan, NULL);
+	_SPI_prepare_oneshot_plan(src, &plan);
 
 	res = _SPI_execute_plan(&plan, NULL,
 							InvalidSnapshot, InvalidSnapshot,
@@ -506,7 +507,7 @@ SPI_execute_with_args(const char *src,
 	paramLI = _SPI_convert_params(nargs, argtypes,
 								  Values, Nulls);
 
-	_SPI_prepare_plan(src, &plan, paramLI);
+	_SPI_prepare_oneshot_plan(src, &plan);
 
 	res = _SPI_execute_plan(&plan, paramLI,
 							InvalidSnapshot, InvalidSnapshot,
@@ -547,7 +548,7 @@ SPI_prepare_cursor(const char *src, int nargs, Oid *argtypes,
 	plan.parserSetup = NULL;
 	plan.parserSetupArg = NULL;
 
-	_SPI_prepare_plan(src, &plan, NULL);
+	_SPI_prepare_plan(src, &plan);
 
 	/* copy plan to procedure context */
 	result = _SPI_make_plan_non_temp(&plan);
@@ -584,7 +585,7 @@ SPI_prepare_params(const char *src,
 	plan.parserSetup = parserSetup;
 	plan.parserSetupArg = parserSetupArg;
 
-	_SPI_prepare_plan(src, &plan, NULL);
+	_SPI_prepare_plan(src, &plan);
 
 	/* copy plan to procedure context */
 	result = _SPI_make_plan_non_temp(&plan);
@@ -599,7 +600,8 @@ SPI_keepplan(SPIPlanPtr plan)
 {
 	ListCell   *lc;
 
-	if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC || plan->saved)
+	if (plan == NULL || plan->magic != _SPI_PLAN_MAGIC ||
+		plan->saved || plan->oneshot)
 		return SPI_ERROR_ARGUMENT;
 
 	/*
@@ -1083,7 +1085,7 @@ SPI_cursor_open_with_args(const char *name,
 	paramLI = _SPI_convert_params(nargs, argtypes,
 								  Values, Nulls);
 
-	_SPI_prepare_plan(src, &plan, paramLI);
+	_SPI_prepare_plan(src, &plan);
 
 	/* We needn't copy the plan; SPI_cursor_open_internal will do so */
 
@@ -1645,10 +1647,6 @@ spi_printtup(TupleTableSlot *slot, DestReceiver *self)
  *
  * At entry, plan->argtypes and plan->nargs (or alternatively plan->parserSetup
  * and plan->parserSetupArg) must be valid, as must plan->cursor_options.
- * If boundParams isn't NULL then it represents parameter values that are made
- * available to the planner (as either estimates or hard values depending on
- * their PARAM_FLAG_CONST marking).  The boundParams had better match the
- * param type information embedded in the plan!
  *
  * Results are stored into *plan (specifically, plan->plancache_list).
  * Note that the result data is all in CurrentMemoryContext or child contexts
@@ -1657,13 +1655,12 @@ spi_printtup(TupleTableSlot *slot, DestReceiver *self)
  * parsing is also left in CurrentMemoryContext.
  */
 static void
-_SPI_prepare_plan(const char *src, SPIPlanPtr plan, ParamListInfo boundParams)
+_SPI_prepare_plan(const char *src, SPIPlanPtr plan)
 {
 	List	   *raw_parsetree_list;
 	List	   *plancache_list;
 	ListCell   *list_item;
 	ErrorContextCallback spierrcontext;
-	int			cursor_options = plan->cursor_options;
 
 	/*
 	 * Setup error traceback support for ereport()
@@ -1726,13 +1723,80 @@ _SPI_prepare_plan(const char *src, SPIPlanPtr plan, ParamListInfo boundParams)
 						   plan->nargs,
 						   plan->parserSetup,
 						   plan->parserSetupArg,
-						   cursor_options,
+						   plan->cursor_options,
 						   false);		/* not fixed result */
 
 		plancache_list = lappend(plancache_list, plansource);
 	}
 
 	plan->plancache_list = plancache_list;
+	plan->oneshot = false;
+
+	/*
+	 * Pop the error context stack
+	 */
+	error_context_stack = spierrcontext.previous;
+}
+
+/*
+ * Parse, but don't analyze, a querystring.
+ *
+ * This is a stripped-down version of _SPI_prepare_plan that only does the
+ * initial raw parsing.  It creates "one shot" CachedPlanSources
+ * that still require parse analysis before execution is possible.
+ *
+ * The advantage of using the "one shot" form of CachedPlanSource is that
+ * we eliminate data copying and invalidation overhead.  Postponing parse
+ * analysis also prevents issues if some of the raw parsetrees are DDL
+ * commands that affect validity of later parsetrees.  Both of these
+ * attributes are good things for SPI_execute() and similar cases.
+ *
+ * Results are stored into *plan (specifically, plan->plancache_list).
+ * Note that the result data is all in CurrentMemoryContext or child contexts
+ * thereof; in practice this means it is in the SPI executor context, and
+ * what we are creating is a "temporary" SPIPlan.  Cruft generated during
+ * parsing is also left in CurrentMemoryContext.
+ */
+static void
+_SPI_prepare_oneshot_plan(const char *src, SPIPlanPtr plan)
+{
+	List	   *raw_parsetree_list;
+	List	   *plancache_list;
+	ListCell   *list_item;
+	ErrorContextCallback spierrcontext;
+
+	/*
+	 * Setup error traceback support for ereport()
+	 */
+	spierrcontext.callback = _SPI_error_callback;
+	spierrcontext.arg = (void *) src;
+	spierrcontext.previous = error_context_stack;
+	error_context_stack = &spierrcontext;
+
+	/*
+	 * Parse the request string into a list of raw parse trees.
+	 */
+	raw_parsetree_list = pg_parse_query(src);
+
+	/*
+	 * Construct plancache entries, but don't do parse analysis yet.
+	 */
+	plancache_list = NIL;
+
+	foreach(list_item, raw_parsetree_list)
+	{
+		Node	   *parsetree = (Node *) lfirst(list_item);
+		CachedPlanSource *plansource;
+
+		plansource = CreateOneShotCachedPlan(parsetree,
+											 src,
+											 CreateCommandTag(parsetree));
+
+		plancache_list = lappend(plancache_list, plansource);
+	}
+
+	plan->plancache_list = plancache_list;
+	plan->oneshot = true;
 
 	/*
 	 * Pop the error context stack
@@ -1770,7 +1834,7 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 	 * Setup error traceback support for ereport()
 	 */
 	spierrcontext.callback = _SPI_error_callback;
-	spierrcontext.arg = NULL;
+	spierrcontext.arg = NULL;	/* we'll fill this below */
 	spierrcontext.previous = error_context_stack;
 	error_context_stack = &spierrcontext;
 
@@ -1817,6 +1881,47 @@ _SPI_execute_plan(SPIPlanPtr plan, ParamListInfo paramLI,
 		spierrcontext.arg = (void *) plansource->query_string;
 
 		/*
+		 * If this is a one-shot plan, we still need to do parse analysis.
+		 */
+		if (plan->oneshot)
+		{
+			Node	   *parsetree = plansource->raw_parse_tree;
+			const char *src = plansource->query_string;
+			List	   *stmt_list;
+
+			/*
+			 * Parameter datatypes are driven by parserSetup hook if provided,
+			 * otherwise we use the fixed parameter list.
+			 */
+			if (plan->parserSetup != NULL)
+			{
+				Assert(plan->nargs == 0);
+				stmt_list = pg_analyze_and_rewrite_params(parsetree,
+														  src,
+														  plan->parserSetup,
+														  plan->parserSetupArg);
+			}
+			else
+			{
+				stmt_list = pg_analyze_and_rewrite(parsetree,
+												   src,
+												   plan->argtypes,
+												   plan->nargs);
+			}
+
+			/* Finish filling in the CachedPlanSource */
+			CompleteCachedPlan(plansource,
+							   stmt_list,
+							   NULL,
+							   plan->argtypes,
+							   plan->nargs,
+							   plan->parserSetup,
+							   plan->parserSetupArg,
+							   plan->cursor_options,
+							   false);		/* not fixed result */
+		}
+
+		/*
 		 * Replan if needed, and increment plan refcount.  If it's a saved
 		 * plan, the refcount must be backed by the CurrentResourceOwner.
 		 */
@@ -2313,6 +2418,8 @@ _SPI_make_plan_non_temp(SPIPlanPtr plan)
 	/* Assert the input is a temporary SPIPlan */
 	Assert(plan->magic == _SPI_PLAN_MAGIC);
 	Assert(plan->plancxt == NULL);
+	/* One-shot plans can't be saved */
+	Assert(!plan->oneshot);
 
 	/*
 	 * Create a memory context for the plan, underneath the procedure context.
@@ -2330,6 +2437,7 @@ _SPI_make_plan_non_temp(SPIPlanPtr plan)
 	newplan = (SPIPlanPtr) palloc(sizeof(_SPI_plan));
 	newplan->magic = _SPI_PLAN_MAGIC;
 	newplan->saved = false;
+	newplan->oneshot = false;
 	newplan->plancache_list = NIL;
 	newplan->plancxt = plancxt;
 	newplan->cursor_options = plan->cursor_options;
@@ -2379,6 +2487,9 @@ _SPI_save_plan(SPIPlanPtr plan)
 	MemoryContext oldcxt;
 	ListCell   *lc;
 
+	/* One-shot plans can't be saved */
+	Assert(!plan->oneshot);
+
 	/*
 	 * Create a memory context for the plan.  We don't expect the plan to be
 	 * very large, so use smaller-than-default alloc parameters.  It's a
@@ -2395,6 +2506,7 @@ _SPI_save_plan(SPIPlanPtr plan)
 	newplan = (SPIPlanPtr) palloc(sizeof(_SPI_plan));
 	newplan->magic = _SPI_PLAN_MAGIC;
 	newplan->saved = false;
+	newplan->oneshot = false;
 	newplan->plancache_list = NIL;
 	newplan->plancxt = plancxt;
 	newplan->cursor_options = plan->cursor_options;