diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 366c50f2730..0f9776cdca2 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.219 2007/05/04 01:13:44 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.220 2007/05/25 17:54:25 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -42,6 +42,10 @@ #include "utils/syscache.h" +/* Hook for plugins to get control in planner() */ +planner_hook_type planner_hook = NULL; + + /* Expression kind codes for preprocess_expression */ #define EXPRKIND_QUAL 0 #define EXPRKIND_TARGET 1 @@ -79,11 +83,31 @@ static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist); * * Query optimizer entry point * + * To support loadable plugins that monitor or modify planner behavior, + * we provide a hook variable that lets a plugin get control before and + * after the standard planning process. The plugin would normally call + * standard_planner(). + * + * Note to plugin authors: standard_planner() scribbles on its Query input, + * so you'd better copy that data structure if you want to plan more than once. + * *****************************************************************************/ PlannedStmt * planner(Query *parse, int cursorOptions, ParamListInfo boundParams) { PlannedStmt *result; + + if (planner_hook) + result = (*planner_hook) (parse, cursorOptions, boundParams); + else + result = standard_planner(parse, cursorOptions, boundParams); + return result; +} + +PlannedStmt * +standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams) +{ + PlannedStmt *result; PlannerGlobal *glob; double tuple_fraction; PlannerInfo *root; |