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Fix EPQ crash from missing partition directory in EState

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EvalPlanQualStart() failed to propagate es_partition_directory into
the child EState used for EPQ rechecks. When execution time partition
pruning ran during the EPQ scan, executor code dereferenced a NULL
partition directory and crashed.

Previously, propagating es_partition_directory into the EPQ EState was
unnecessary because CreatePartitionPruneState(), which sets it on
demand, also initialized the exec-pruning context.  After commit
d47cbf474, CreatePartitionPruneState() now initializes only the init-
time pruning context, leaving exec-pruning context initialization to
ExecInitNode(). Since EvalPlanQualStart() runs only ExecInitNode() and
not CreatePartitionPruneState(), it can encounter a NULL
es_partition_directory.  Other executor fields initialized during
CreatePartitionPruneState() are already copied into the child EState
thanks to commit 8741e48e5d, but es_partition_directory was missed.

Fix by borrowing the parent estate's  es_partition_directory in
EvalPlanQualStart(), and by clearing that field in EvalPlanQualEnd()
so the parent remains responsible for freeing the directory.

Add an isolation test permutation that triggers EPQ with execution-
time partition pruning, the case that reproduces this crash.

Bug: #19078
Reported-by: Yuri Zamyatin <yuri@yrz.am>
Diagnosed-by: David Rowley <dgrowleyml@gmail.com>
Author: David Rowley <dgrowleyml@gmail.com>
Co-authored-by: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/19078-dfd62f840a2c0766@postgresql.org
Backpatch-through: 18
This commit is contained in:
Amit Langote
2025-10-16 14:01:44 +09:00
parent 02c171f63f
commit 905e932f09
3 changed files with 19 additions and 0 deletions
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10
src/backend/executor/execMain.c
View File

@@ -3093,6 +3093,9 @@ EvalPlanQualStart(EPQState *epqstate, Plan *planTree)
rcestate->es_part_prune_states = parentestate->es_part_prune_states; rcestate->es_part_prune_states = parentestate->es_part_prune_states;
rcestate->es_part_prune_results = parentestate->es_part_prune_results; rcestate->es_part_prune_results = parentestate->es_part_prune_results;
/* We'll also borrow the es_partition_directory from the parent state */
rcestate->es_partition_directory = parentestate->es_partition_directory;
/* /*
* Initialize private state information for each SubPlan. We must do this * Initialize private state information for each SubPlan. We must do this
* before running ExecInitNode on the main query tree, since * before running ExecInitNode on the main query tree, since
@@ -3210,6 +3213,13 @@ EvalPlanQualEnd(EPQState *epqstate)
MemoryContextSwitchTo(oldcontext); MemoryContextSwitchTo(oldcontext);
/*
* NULLify the partition directory before freeing the executor state.
* Since EvalPlanQualStart() just borrowed the parent EState's directory,
* we'd better leave it up to the parent to delete it.
*/
estate->es_partition_directory = NULL;
FreeExecutorState(estate); FreeExecutorState(estate);
/* Mark EPQState idle */ /* Mark EPQState idle */

7
src/test/isolation/expected/eval-plan-qual.out
View File

@@ -1466,3 +1466,10 @@ step s2pp3: EXECUTE epd(1); <waiting ...>
step c1: COMMIT; step c1: COMMIT;
step s2pp3: <... completed> step s2pp3: <... completed>
step c2: COMMIT; step c2: COMMIT;
starting permutation: s1pp1 s2pp4 c1 c2
step s1pp1: UPDATE another_parttbl SET b = b + 1 WHERE a = 1;
step s2pp4: DELETE FROM another_parttbl WHERE a = (SELECT 1); <waiting ...>
step c1: COMMIT;
step s2pp4: <... completed>
step c2: COMMIT;

2
src/test/isolation/specs/eval-plan-qual.spec
View File

@@ -316,6 +316,7 @@ step r2 { ROLLBACK; }
step s2pp1 { SET plan_cache_mode TO force_generic_plan; } step s2pp1 { SET plan_cache_mode TO force_generic_plan; }
step s2pp2 { PREPARE epd AS DELETE FROM another_parttbl WHERE a = $1; } step s2pp2 { PREPARE epd AS DELETE FROM another_parttbl WHERE a = $1; }
step s2pp3 { EXECUTE epd(1); } step s2pp3 { EXECUTE epd(1); }
step s2pp4 { DELETE FROM another_parttbl WHERE a = (SELECT 1); }
session s3 session s3
setup { BEGIN ISOLATION LEVEL READ COMMITTED; } setup { BEGIN ISOLATION LEVEL READ COMMITTED; }
@@ -423,3 +424,4 @@ permutation sys1 sysmerge2 c1 c2
# Exercise run-time partition pruning code in an EPQ recheck # Exercise run-time partition pruning code in an EPQ recheck
permutation s1pp1 s2pp1 s2pp2 s2pp3 c1 c2 permutation s1pp1 s2pp1 s2pp2 s2pp3 c1 c2
permutation s1pp1 s2pp4 c1 c2