From c6bb0fb8a8c00c495d08b6a74f70c0c5df89a665 Mon Sep 17 00:00:00 2001 From: Hou Zhijie Date: Thu, 7 Sep 2023 19:44:42 +0800 Subject: [PATCH] Reset InitialRunningXacts at memory context reset callback The transactions and subtransactions array that were recorded during decoding were not cleared in case of errors. This can result in an assert failure if we attempt to retry logical decoding within the same session. To address this issue, we register a callback function under the snapshot builder memory context to clear the recorded transactions and subtransactions. --- src/backend/replication/logical/snapbuild.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c index 02d73e5c93..e32ed39e28 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -336,6 +336,17 @@ SnapBuildStartNextPhaseAt(SnapBuild *builder, TransactionId at) builder->was_running.was_xmax = at; } +/* + * Memory context reset callback for clearing the array of running transactions + * and subtransactions. + */ +static void +SnapBuildResetRunningXactsCallback(void *arg) +{ + NInitialRunningXacts = 0; + InitialRunningXacts = NULL; +} + /* * Allocate a new snapshot builder. * @@ -351,6 +362,7 @@ AllocateSnapshotBuilder(ReorderBuffer *reorder, MemoryContext context; MemoryContext oldcontext; SnapBuild *builder; + MemoryContextCallback *mcallback; /* allocate memory in own context, to have better accountability */ context = AllocSetContextCreate(CurrentMemoryContext, @@ -375,6 +387,10 @@ AllocateSnapshotBuilder(ReorderBuffer *reorder, builder->start_decoding_at = start_lsn; builder->building_full_snapshot = need_full_snapshot; + mcallback = palloc0(sizeof(MemoryContextCallback)); + mcallback->func = SnapBuildResetRunningXactsCallback; + MemoryContextRegisterResetCallback(CurrentMemoryContext, mcallback); + MemoryContextSwitchTo(oldcontext); /* The initial running transactions array must be empty. */ @@ -400,10 +416,6 @@ FreeSnapshotBuilder(SnapBuild *builder) /* other resources are deallocated via memory context reset */ MemoryContextDelete(context); - - /* InitialRunningXacts is freed along with the context */ - NInitialRunningXacts = 0; - InitialRunningXacts = NULL; } /* -- 2.30.0.windows.2