From 0f4c170cf3b85ef8b092990a88e5b7b50892f7d5 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Mon, 30 Mar 2026 09:38:03 -0400 Subject: [PATCH] Make it cheap to check if a relation is modified by a query Save the range table indexes of result relations and row mark relations in separate bitmapsets in the PlannedStmt. Precomputing them allows cheap membership checks during execution. Together, these two groups approximate all relations that will be modified by a query. This includes relations targeted by INSERT, UPDATE, DELETE, and MERGE as well as relations with any row mark (like SELECT FOR UPDATE). Future work will use information on whether or not a relation is modified by a query in a heuristic. PlannedStmt->resultRelations is only used in a membership check, so it will be removed in a separate commit. Author: Melanie Plageman Reviewed-by: Andres Freund Reviewed-by: David Rowley Reviewed-by: Chao Li Discussion: https://postgr.es/m/F5CDD1B5-628C-44A1-9F85-3958C626F6A9%40gmail.com --- src/backend/executor/execParallel.c | 7 +++++++ src/backend/optimizer/plan/planner.c | 15 ++++++++++++++- src/include/nodes/plannodes.h | 6 ++++++ 3 files changed, 27 insertions(+), 1 deletion(-) diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c index ac84af294c9..f203ed85f50 100644 --- a/src/backend/executor/execParallel.c +++ b/src/backend/executor/execParallel.c @@ -212,6 +212,13 @@ ExecSerializePlan(Plan *plan, EState *estate) pstmt->rewindPlanIDs = NULL; pstmt->rowMarks = NIL; + + /* + * Pass the row mark and result relation relids to parallel workers. They + * may need to check them to inform heuristics. + */ + pstmt->rowMarkRelids = estate->es_plannedstmt->rowMarkRelids; + pstmt->resultRelationRelids = estate->es_plannedstmt->resultRelationRelids; pstmt->relationOids = NIL; pstmt->invalItems = NIL; /* workers can't replan anyway... */ pstmt->paramExecTypes = estate->es_plannedstmt->paramExecTypes; diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index d19800ad6a5..c81eb76ad75 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -341,7 +341,8 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, Path *best_path; Plan *top_plan; ListCell *lp, - *lr; + *lr, + *lc; /* * Set up global state for this planner invocation. This data is needed @@ -661,6 +662,18 @@ standard_planner(Query *parse, const char *query_string, int cursorOptions, result->subplans = glob->subplans; result->rewindPlanIDs = glob->rewindPlanIDs; result->rowMarks = glob->finalrowmarks; + + /* + * Compute resultRelationRelids and rowMarkRelids from resultRelations and + * rowMarks. These can be used for cheap membership checks. + */ + foreach(lc, glob->resultRelations) + result->resultRelationRelids = bms_add_member(result->resultRelationRelids, + lfirst_int(lc)); + foreach(lc, glob->finalrowmarks) + result->rowMarkRelids = bms_add_member(result->rowMarkRelids, + ((PlanRowMark *) lfirst(lc))->rti); + result->relationOids = glob->relationOids; result->invalItems = glob->invalItems; result->paramExecTypes = glob->paramExecTypes; diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h index b6185825fcb..ca61ecfc132 100644 --- a/src/include/nodes/plannodes.h +++ b/src/include/nodes/plannodes.h @@ -121,6 +121,9 @@ typedef struct PlannedStmt /* integer list of RT indexes, or NIL */ List *resultRelations; + /* RT indexes of relations targeted by INSERT/UPDATE/DELETE/MERGE */ + Bitmapset *resultRelationRelids; + /* list of AppendRelInfo nodes */ List *appendRelations; @@ -138,6 +141,9 @@ typedef struct PlannedStmt /* a list of PlanRowMark's */ List *rowMarks; + /* RT indexes of relations with row marks */ + Bitmapset *rowMarkRelids; + /* OIDs of relations the plan depends on */ List *relationOids;