Allow the planner-related functions and hook to accept the query string.

This commit adds query_string argument into the planner-related functions
and hook and allows us to pass the query string to them.

Currently there is no user of the query string passed. But the upcoming patch
for the planning counters will add the planning hook function into
pg_stat_statements and the function will need the query string. So this change
will be necessary for that patch.

Also this change is useful for some extensions that want to use the query
string in their planner hook function.

Author: Pascal Legrand, Julien Rouhaud
Reviewed-by: Yoshikazu Imai, Tom Lane, Fujii Masao
Discussion: https://postgr.es/m/CAOBaU_bU1m3_XF5qKYtSj1ua4dxd=FWDyh2SH4rSJAUUfsGmAQ@mail.gmail.com
Discussion: https://postgr.es/m/1583789487074-0.post@n3.nabble.com

src/backend/commands/copy.c

@@ -1580,7 +1580,8 @@ BeginCopy(ParseState *pstate,
 		}
 
 		/* plan the query */
-		plan = pg_plan_query(query, CURSOR_OPT_PARALLEL_OK, NULL);
+		plan = pg_plan_query(query, pstate->p_sourcetext,
+							 CURSOR_OPT_PARALLEL_OK, NULL);
 
 		/*
 		 * With row level security and a user using "COPY relation TO", we

src/backend/commands/createas.c

@@ -329,7 +329,8 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
 		Assert(query->commandType == CMD_SELECT);
 
 		/* plan the query */
-		plan = pg_plan_query(query, CURSOR_OPT_PARALLEL_OK, params);
+		plan = pg_plan_query(query, pstate->p_sourcetext,
+							 CURSOR_OPT_PARALLEL_OK, params);
 
 		/*
 		 * Use a snapshot with an updated command ID to ensure this query sees

src/backend/commands/explain.c

@@ -376,7 +376,7 @@ ExplainOneQuery(Query *query, int cursorOptions,
 		INSTR_TIME_SET_CURRENT(planstart);
 
 		/* plan the query */
-		plan = pg_plan_query(query, cursorOptions, params);
+		plan = pg_plan_query(query, queryString, cursorOptions, params);
 
 		INSTR_TIME_SET_CURRENT(planduration);
 		INSTR_TIME_SUBTRACT(planduration, planstart);

src/backend/commands/extension.c

@@ -751,7 +751,7 @@ execute_sql_string(const char *sql)
 										   NULL,
 										   0,
 										   NULL);
-		stmt_list = pg_plan_queries(stmt_list, CURSOR_OPT_PARALLEL_OK, NULL);
+		stmt_list = pg_plan_queries(stmt_list, sql, CURSOR_OPT_PARALLEL_OK, NULL);
 
 		foreach(lc2, stmt_list)
 		{

src/backend/commands/matview.c

@@ -391,7 +391,7 @@ refresh_matview_datafill(DestReceiver *dest, Query *query,
 	CHECK_FOR_INTERRUPTS();
 
 	/* Plan the query which will generate data for the refresh. */
-	plan = pg_plan_query(query, 0, NULL);
+	plan = pg_plan_query(query, queryString, 0, NULL);
 
 	/*
 	 * Use a snapshot with an updated command ID to ensure this query sees

src/backend/commands/portalcmds.c

@@ -90,7 +90,7 @@ PerformCursorOpen(ParseState *pstate, DeclareCursorStmt *cstmt, ParamListInfo pa
 		elog(ERROR, "non-SELECT statement in DECLARE CURSOR");
 
 	/* Plan the query, applying the specified options */
-	plan = pg_plan_query(query, cstmt->options, params);
+	plan = pg_plan_query(query, pstate->p_sourcetext, cstmt->options, params);
 
 	/*
 	 * Create a portal and copy the plan and query string into its memory.

src/backend/executor/functions.c

@@ -510,6 +510,7 @@ init_execution_state(List *queryTree_list,
 			}
 			else
 				stmt = pg_plan_query(queryTree,
+									 fcache->src,
 									 CURSOR_OPT_PARALLEL_OK,
 									 NULL);
 

src/backend/optimizer/plan/planner.c

@@ -264,19 +264,21 @@ static int	common_prefix_cmp(const void *a, const void *b);
  *
  *****************************************************************************/
 PlannedStmt *
-planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
+planner(Query *parse, const char *query_string, int cursorOptions,
+		ParamListInfo boundParams)
 {
 	PlannedStmt *result;
 
 	if (planner_hook)
-		result = (*planner_hook) (parse, cursorOptions, boundParams);
+		result = (*planner_hook) (parse, query_string, cursorOptions, boundParams);
 	else
-		result = standard_planner(parse, cursorOptions, boundParams);
+		result = standard_planner(parse, query_string, cursorOptions, boundParams);
 	return result;
 }
 
 PlannedStmt *
-standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
+standard_planner(Query *parse, const char *query_string, int cursorOptions,
+				 ParamListInfo boundParams)
 {
 	PlannedStmt *result;
 	PlannerGlobal *glob;

src/backend/tcop/postgres.c

@@ -854,7 +854,8 @@ pg_rewrite_query(Query *query)
  * This is a thin wrapper around planner() and takes the same parameters.
  */
 PlannedStmt *
-pg_plan_query(Query *querytree, int cursorOptions, ParamListInfo boundParams)
+pg_plan_query(Query *querytree, const char *query_string, int cursorOptions,
+			  ParamListInfo boundParams)
 {
 	PlannedStmt *plan;
 
@@ -871,7 +872,7 @@ pg_plan_query(Query *querytree, int cursorOptions, ParamListInfo boundParams)
 		ResetUsage();
 
 	/* call the optimizer */
-	plan = planner(querytree, cursorOptions, boundParams);
+	plan = planner(querytree, query_string, cursorOptions, boundParams);
 
 	if (log_planner_stats)
 		ShowUsage("PLANNER STATISTICS");
@@ -939,7 +940,8 @@ pg_plan_query(Query *querytree, int cursorOptions, ParamListInfo boundParams)
  * The result is a list of PlannedStmt nodes.
  */
 List *
-pg_plan_queries(List *querytrees, int cursorOptions, ParamListInfo boundParams)
+pg_plan_queries(List *querytrees, const char *query_string, int cursorOptions,
+				ParamListInfo boundParams)
 {
 	List	   *stmt_list = NIL;
 	ListCell   *query_list;
@@ -961,7 +963,8 @@ pg_plan_queries(List *querytrees, int cursorOptions, ParamListInfo boundParams)
 		}
 		else
 		{
-			stmt = pg_plan_query(query, cursorOptions, boundParams);
+			stmt = pg_plan_query(query, query_string, cursorOptions,
+								 boundParams);
 		}
 
 		stmt_list = lappend(stmt_list, stmt);
@@ -1152,7 +1155,7 @@ exec_simple_query(const char *query_string)
 		querytree_list = pg_analyze_and_rewrite(parsetree, query_string,
 												NULL, 0, NULL);
 
-		plantree_list = pg_plan_queries(querytree_list,
+		plantree_list = pg_plan_queries(querytree_list, query_string,
 										CURSOR_OPT_PARALLEL_OK, NULL);
 
 		/*

src/backend/utils/cache/plancache.c

@@ -930,7 +930,8 @@ BuildCachedPlan(CachedPlanSource *plansource, List *qlist,
 	/*
 	 * Generate the plan.
 	 */
-	plist = pg_plan_queries(qlist, plansource->cursor_options, boundParams);
+	plist = pg_plan_queries(qlist, plansource->query_string,
+							plansource->cursor_options, boundParams);
 
 	/* Release snapshot if we got one */
 	if (snapshot_set)

src/include/optimizer/optimizer.h

@@ -102,7 +102,8 @@ typedef enum
 extern int	force_parallel_mode;
 extern bool parallel_leader_participation;
 
-extern struct PlannedStmt *planner(Query *parse, int cursorOptions,
+extern struct PlannedStmt *planner(Query *parse, const char *query_string,
+								   int cursorOptions,
 								   struct ParamListInfoData *boundParams);
 
 extern Expr *expression_planner(Expr *expr);

src/include/optimizer/planner.h

@@ -24,6 +24,7 @@
 
 /* Hook for plugins to get control in planner() */
 typedef PlannedStmt *(*planner_hook_type) (Query *parse,
+										   const char *query_string,
 										   int cursorOptions,
 										   ParamListInfo boundParams);
 extern PGDLLIMPORT planner_hook_type planner_hook;
@@ -37,7 +38,8 @@ typedef void (*create_upper_paths_hook_type) (PlannerInfo *root,
 extern PGDLLIMPORT create_upper_paths_hook_type create_upper_paths_hook;
 
 
-extern PlannedStmt *standard_planner(Query *parse, int cursorOptions,
+extern PlannedStmt *standard_planner(Query *parse, const char *query_string,
+									 int cursorOptions,
 									 ParamListInfo boundParams);
 
 extern PlannerInfo *subquery_planner(PlannerGlobal *glob, Query *parse,

src/include/tcop/tcopprot.h

@@ -52,9 +52,11 @@ extern List *pg_analyze_and_rewrite_params(RawStmt *parsetree,
 										   ParserSetupHook parserSetup,
 										   void *parserSetupArg,
 										   QueryEnvironment *queryEnv);
-extern PlannedStmt *pg_plan_query(Query *querytree, int cursorOptions,
+extern PlannedStmt *pg_plan_query(Query *querytree, const char *query_string,
+								  int cursorOptions,
 								  ParamListInfo boundParams);
-extern List *pg_plan_queries(List *querytrees, int cursorOptions,
+extern List *pg_plan_queries(List *querytrees, const char *query_string,
+							 int cursorOptions,
 							 ParamListInfo boundParams);
 
 extern bool check_max_stack_depth(int *newval, void **extra, GucSource source);