postgres.git / summary / log / commit / refs

commit    2fa42feb7921d9486d56a38608d2b27b8f4e607c
Author:   Tomas Vondra <tomas.vondra@postgresql.org>
Date:     Sat Mar 14 14:24:37 2026 +0000
First released in: 14.23, 15.18, 16.14, 17.10, 18.4

    Tighten asserts on ParallelWorkerNumber
    
    The comment about ParallelWorkerNumbr in parallel.c says:
    
      In parallel workers, it will be set to a value >= 0 and < the number
      of workers before any user code is invoked; each parallel worker will
      get a different parallel worker number.
    
    However asserts in various places collecting instrumentation allowed
    (ParallelWorkerNumber == num_workers). That would be a bug, as the value
    is used as index into an array with num_workers entries.
    
    Fixed by adjusting the asserts accordingly. Backpatch to all supported
    versions.
    
    Discussion: https://postgr.es/m/5db067a1-2cdf-4afb-a577-a04f30b69167@vondra.me
    Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
    Backpatch-through: 14


 src/backend/executor/nodeAgg.c             | 2 +-
 src/backend/executor/nodeIncrementalSort.c | 2 +-
 src/backend/executor/nodeMemoize.c         | 2 +-
 src/backend/executor/nodeSort.c            | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 53ead77ece8..bb6f55b2c75 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -4317,7 +4317,7 @@ ExecEndAgg(AggState *node)
 	{
 		AggregateInstrumentation *si;
 
-		Assert(ParallelWorkerNumber <= node->shared_info->num_workers);
+		Assert(ParallelWorkerNumber < node->shared_info->num_workers);
 		si = &node->shared_info->sinstrument[ParallelWorkerNumber];
 		si->hash_batches_used = node->hash_batches_used;
 		si->hash_disk_used = node->hash_disk_used;
diff --git a/src/backend/executor/nodeIncrementalSort.c b/src/backend/executor/nodeIncrementalSort.c
index 2ce5ed5ec8c..235fb90564a 100644
--- a/src/backend/executor/nodeIncrementalSort.c
+++ b/src/backend/executor/nodeIncrementalSort.c
@@ -102,7 +102,7 @@
 			if ((node)->shared_info && (node)->am_worker) \
 			{ \
 				Assert(IsParallelWorker()); \
-				Assert(ParallelWorkerNumber <= (node)->shared_info->num_workers); \
+				Assert(ParallelWorkerNumber < (node)->shared_info->num_workers); \
 				instrumentSortedGroup(&(node)->shared_info->sinfo[ParallelWorkerNumber].groupName##GroupInfo, \
 									  (node)->groupName##_state); \
 			} \
diff --git a/src/backend/executor/nodeMemoize.c b/src/backend/executor/nodeMemoize.c
index 45157ffb9c7..79ed1cf7f0c 100644
--- a/src/backend/executor/nodeMemoize.c
+++ b/src/backend/executor/nodeMemoize.c
@@ -1122,7 +1122,7 @@ ExecEndMemoize(MemoizeState *node)
 		if (node->stats.mem_peak == 0)
 			node->stats.mem_peak = node->mem_used;
 
-		Assert(ParallelWorkerNumber <= node->shared_info->num_workers);
+		Assert(ParallelWorkerNumber < node->shared_info->num_workers);
 		si = &node->shared_info->sinstrument[ParallelWorkerNumber];
 		memcpy(si, &node->stats, sizeof(MemoizeInstrumentation));
 	}
diff --git a/src/backend/executor/nodeSort.c b/src/backend/executor/nodeSort.c
index 3fc925d7b48..c1b8cc913d5 100644
--- a/src/backend/executor/nodeSort.c
+++ b/src/backend/executor/nodeSort.c
@@ -175,7 +175,7 @@ ExecSort(PlanState *pstate)
 			TuplesortInstrumentation *si;
 
 			Assert(IsParallelWorker());
-			Assert(ParallelWorkerNumber <= node->shared_info->num_workers);
+			Assert(ParallelWorkerNumber < node->shared_info->num_workers);
 			si = &node->shared_info->sinstrument[ParallelWorkerNumber];
 			tuplesort_get_stats(tuplesortstate, si);
 		}


[parent: 6ef36bb35884]