From 699242f521ca30283cc42236617e9c118ad165c0 Mon Sep 17 00:00:00 2001 From: Hou Zhijie Date: Thu, 24 Aug 2023 11:33:12 +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 4c951678c0..3eaaaac6b3 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -300,6 +300,17 @@ static void SnapBuildWaitSnapshot(xl_running_xacts *running, TransactionId cutof static void SnapBuildSerialize(SnapBuild *builder, XLogRecPtr lsn); static bool SnapBuildRestore(SnapBuild *builder, XLogRecPtr lsn); +/* + * 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. * @@ -316,6 +327,7 @@ AllocateSnapshotBuilder(ReorderBuffer *reorder, MemoryContext context; MemoryContext oldcontext; SnapBuild *builder; + MemoryContextCallback *mcallback; /* allocate memory in own context, to have better accountability */ context = AllocSetContextCreate(CurrentMemoryContext, @@ -341,6 +353,10 @@ AllocateSnapshotBuilder(ReorderBuffer *reorder, builder->building_full_snapshot = need_full_snapshot; builder->two_phase_at = two_phase_at; + mcallback = palloc0(sizeof(MemoryContextCallback)); + mcallback->func = SnapBuildResetRunningXactsCallback; + MemoryContextRegisterResetCallback(CurrentMemoryContext, mcallback); + MemoryContextSwitchTo(oldcontext); /* The initial running transactions array must be empty. */ @@ -366,10 +382,6 @@ 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