提交: 647bad47746afec7b58d3a498bce6f36bd9ae984 - amalsyah12 (git)

firtst release

Commit MetaInfo

• 修訂: 647bad47746afec7b58d3a498bce6f36bd9ae984 (tree)
• 時間: 2019-02-26 17:49:50
• 作者: Kyotaro Horiguchi <horiguchi.kyotaro@lab....>
• Commiter: Kyotaro Horiguchi

Log Message

Correctly handle planner nesting

pg_hint_plan assumed that plpgsql is the only source of nested planner
calls. Actually nested call can be made in any shapes. Most of the
cases doesn't harm but in a special case where pg_dbms_stats makes a
SPI call during query planning, that affects subsequent planner
work. Hints lose effect when pg_dbms_stats searches "locked
statistics" tables while planning the target query.

Change Summary

• modified: pg_hint_plan.c

差異

--- a/pg_hint_plan.c
+++ b/pg_hint_plan.c
@@ -521,6 +521,7 @@ static int	pg_hint_plan_debug_message_level = LOG;
 static bool	pg_hint_plan_enable_hint_table = false;
 
 static int plpgsql_recurse_level = 0;		/* PLpgSQL recursion level            */
+static int recurse_level = 0;		/* recursion level incl. direct SPI calls */
 static int hint_inhibit_level = 0;			/* Inhibit hinting if this is above 0 */
 											/* (This could not be above 1)        */
 static int max_hint_nworkers = -1;		/* Maximum nworkers of Workers hints */
@@ -2993,6 +2994,7 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 	int				save_nestlevel;
 	PlannedStmt	   *result;
 	HintState	   *hstate;
+	const char 	   *prev_hint_str;
 
 	/*
 	 * Use standard planner if pg_hint_plan is disabled or current nesting 
@@ -3021,9 +3023,6 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 	{
 		MemoryContext oldcontext;
 
-		if (current_hint_str)
-			pfree((void *)current_hint_str);
-
 		oldcontext = MemoryContextSwitchTo(TopMemoryContext);
 		current_hint_str =
 			get_hints_from_comment((char *)error_context_stack->arg);
@@ -3093,10 +3092,21 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 	 */
 	PG_TRY();
 	{
+		/*
+		 * The planner call below may replace current_hint_str. Store and
+		 * restore it so that the subsequent planning in the upper level
+		 * doesn't get confused.
+		 */
+		recurse_level++;
+		prev_hint_str = current_hint_str;
+
 		if (prev_planner)
 			result = (*prev_planner) (parse, cursorOptions, boundParams);
 		else
 			result = standard_planner(parse, cursorOptions, boundParams);
+
+		current_hint_str = prev_hint_str;
+		recurse_level--;
 	}
 	PG_CATCH();
 	{
@@ -3104,6 +3114,8 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 		 * Rollback changes of GUC parameters, and pop current hint context
 		 * from hint stack to rewind the state.
 		 */
+		current_hint_str = prev_hint_str;
+		recurse_level--;
 		AtEOXact_GUC(true, save_nestlevel);
 		pop_hint();
 		PG_RE_THROW();
@@ -3114,7 +3126,7 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
 	/*
 	 * current_hint_str is useless after planning of the top-level query.
 	 */
-	if (plpgsql_recurse_level < 1 && current_hint_str)
+	if (recurse_level < 1 && current_hint_str)
 	{
 		pfree((void *)current_hint_str);
 		current_hint_str = NULL;