From 9671bc3cbb6f204e521be0861affdeefa42abd17 Mon Sep 17 00:00:00 2001 From: Murat Tuncer Date: Fri, 21 Dec 2018 15:27:15 +0300 Subject: [PATCH] Make sure spinlock is not left unreleased when an exception is thrown A spinlock is not released when an exception is thrown after spinlock is acquired. This has caused infinite wait and eventual crash in maintenance daemon. This work moves the code than can fail to the outside of spinlock scope so that in the case of failure spinlock is not left locked since it was not locked in the first place. --- src/backend/distributed/transaction/backend_data.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/src/backend/distributed/transaction/backend_data.c b/src/backend/distributed/transaction/backend_data.c index 70820b219..eba215fa6 100644 --- a/src/backend/distributed/transaction/backend_data.c +++ b/src/backend/distributed/transaction/backend_data.c @@ -829,9 +829,15 @@ AssignDistributedTransactionId(void) void MarkCitusInitiatedCoordinatorBackend(void) { + /* + * GetLocalGroupId may throw exception which can cause leaving spin lock + * unreleased. Calling GetLocalGroupId function before the lock to avoid this. + */ + int localGroupId = GetLocalGroupId(); + SpinLockAcquire(&MyBackendData->mutex); - MyBackendData->citusBackend.initiatorNodeIdentifier = GetLocalGroupId(); + MyBackendData->citusBackend.initiatorNodeIdentifier = localGroupId; MyBackendData->citusBackend.transactionOriginator = true; SpinLockRelease(&MyBackendData->mutex);