Fix EPQ crash from missing partition pruning state in EState

amitlan · amitlan · commit 9a82a64edcd8 · 2025-09-19T11:39:06.000+09:00
Commit bb3ec16 moved partition pruning metadata into PlannedStmt. At executor startup this metadata is used to initialize the EState fields es_part_prune_infos, es_part_prune_states, and es_part_prune_results. EvalPlanQualStart() failed to copy those fields into the child EState, causing NULL dereference when Append ran partition pruning during a recheck. This can occur with DELETE or UPDATE on partitioned tables that use runtime pruning, e.g. with generic plans. Fix by copying all partition pruning state into the EPQ estate. Add an isolation test that reproduces the crash with concurrent UPDATE and DELETE on a partitioned table, where the DELETE session hits the crash during its EPQ recheck after the UPDATE commits. Bug: #19056 Reported-by: Fei Changhong <feichanghong@qq.com> Diagnozed-by: Fei Changhong <feichanghong@qq.com> Author: David Rowley <dgrowleyml@gmail.com> Co-authored-by: Amit Langote <amitlangote09@gmail.com> Discussion: https://postgr.es/m/19056-a677cef9b54d76a0%40postgresql.org
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
@@ -3084,6 +3084,15 @@ EvalPlanQualStart(EPQState *epqstate, Plan *planTree)
 	 */
 	rcestate->es_unpruned_relids = parentestate->es_unpruned_relids;
 
+	/*
+	 * Also make the PartitionPruneInfo and the results of pruning available.
+	 * These need to match exactly so that we initialize all the same Append
+	 * and MergeAppend subplans as the parent did.
+	 */
+	rcestate->es_part_prune_infos = parentestate->es_part_prune_infos;
+	rcestate->es_part_prune_states = parentestate->es_part_prune_states;
+	rcestate->es_part_prune_results = parentestate->es_part_prune_results;
+
 	/*
 	 * Initialize private state information for each SubPlan.  We must do this
 	 * before running ExecInitNode on the main query tree, since
diff --git a/src/test/isolation/expected/eval-plan-qual.out b/src/test/isolation/expected/eval-plan-qual.out
@@ -1457,3 +1457,12 @@ step sysmerge2:
 step c1: COMMIT;
 step sysmerge2: <... completed>
 step c2: COMMIT;
+
+starting permutation: s1pp1 s2pp1 s2pp2 s2pp3 c1 c2
+step s1pp1: UPDATE another_parttbl SET b = b + 1 WHERE a = 1;
+step s2pp1: SET plan_cache_mode TO force_generic_plan;
+step s2pp2: PREPARE epd AS DELETE FROM another_parttbl WHERE a = $1;
+step s2pp3: EXECUTE epd(1); <waiting ...>
+step c1: COMMIT;
+step s2pp3: <... completed>
+step c2: COMMIT;
diff --git a/src/test/isolation/specs/eval-plan-qual.spec b/src/test/isolation/specs/eval-plan-qual.spec
@@ -204,6 +204,7 @@ step sys1	{
 	UPDATE pg_class SET reltuples = 123 WHERE oid = 'accounts'::regclass;
 }
 
+step s1pp1 { UPDATE another_parttbl SET b = b + 1 WHERE a = 1; }
 
 session s2
 setup		{ BEGIN ISOLATION LEVEL READ COMMITTED; }
@@ -312,6 +313,10 @@ step sysmerge2	{
 step c2	{ COMMIT; }
 step r2	{ ROLLBACK; }
 
+step s2pp1 { SET plan_cache_mode TO force_generic_plan; }
+step s2pp2 { PREPARE epd AS DELETE FROM another_parttbl WHERE a = $1; }
+step s2pp3 { EXECUTE epd(1); }
+
 session s3
 setup		{ BEGIN ISOLATION LEVEL READ COMMITTED; }
 step read	{ SELECT * FROM accounts ORDER BY accountid; }
@@ -415,3 +420,6 @@ permutation simplepartupdate_noroute complexpartupdate_doesnt_route c1 c2 read_p
 
 permutation sys1 sysupd2 c1 c2
 permutation sys1 sysmerge2 c1 c2
+
+# Exercise run-time partition pruning code in an EPQ recheck
+permutation s1pp1 s2pp1 s2pp2 s2pp3 c1 c2
