From b0c592eb94aac365a748167ceab1414f0d206c70 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Thu, 31 Jul 2025 23:39:15 +0900 Subject: [PATCH v1] Fix assertion failure in pgbench when handling multiple pipeline sync messages. Previously, when running pgbench in pipeline mode with a custom script that triggered errors, an assertion failure could occur: Assertion failed: (res == ((void*)0)), function discardUntilSync, file pgbench.c, line 3515. The root cause was that pgbench incorrectly assumed only a single pipeline sync message would be received at the end. In reality, multiple pipeline sync messages can be sent and must be handled properly. This commit fixes the issue by updating pgbench to correctly process multiple pipeline sync messages, preventing the assertion failure. --- src/bin/pgbench/pgbench.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c index 497a936c141..125f3c7bbbe 100644 --- a/src/bin/pgbench/pgbench.c +++ b/src/bin/pgbench/pgbench.c @@ -3495,6 +3495,8 @@ doRetry(CState *st, pg_time_usec_t *now) static int discardUntilSync(CState *st) { + bool received_sync = false; + /* send a sync */ if (!PQpipelineSync(st->con)) { @@ -3509,10 +3511,21 @@ discardUntilSync(CState *st) PGresult *res = PQgetResult(st->con); if (PQresultStatus(res) == PGRES_PIPELINE_SYNC) + received_sync = true; + else if (received_sync) { - PQclear(res); - res = PQgetResult(st->con); + /* + * PGRES_PIPELINE_SYNC must be followed by another + * PGRES_PIPELINE_SYNC or NULL; otherwise, assert failure. + */ Assert(res == NULL); + + /* + * Reset ongoing sync count to 0 since all PGRES_PIPELINE_SYNC + * results have been discarded. + */ + st->num_syncs = 0; + PQclear(res); break; } PQclear(res); -- 2.50.1