From 6c8671bc395c9be44571e424c458b94ec20975d3 Mon Sep 17 00:00:00 2001 From: Amit Kapila Date: Fri, 28 Sep 2018 12:24:09 +0530 Subject: [PATCH] Fix assertion failure when updating full_page_writes for checkpointer. When the checkpointer receives a SIGHUP signal to update its configuration, it may need to update the shared memory for full_page_writes and need to write a WAL record for it. Now, it is quite possible that the XLOG machinery has not been initialized by that time and it will lead to assertion failure while doing that. Fix is to allow the initialization of the XLOG machinery outside critical section. This bug has been introduced by the commit 2c03216d83 which added the XLOG machinery initialization in RecoveryInProgress code path. Reported-by: Dilip Kumar Author: Dilip Kumar Reviewed-by: Michael Paquier and Amit Kapila Backpatch-through: 9.5 Discussion: https://postgr.es/m/CAFiTN-u4BA8KXcQUWDPNgaKAjDXC=C2whnzBM8TAcv=stckYUw@mail.gmail.com --- src/backend/access/transam/xlog.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 9331306cba..e941d7d253 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -9634,6 +9634,7 @@ void UpdateFullPageWrites(void) { XLogCtlInsert *Insert = &XLogCtl->Insert; + bool recoveryInProgress; /* * Do nothing if full_page_writes has not been changed. @@ -9645,6 +9646,13 @@ UpdateFullPageWrites(void) if (fullPageWrites == Insert->fullPageWrites) return; + /* + * Perform this outside critical section so that the WAL insert + * initialization done by RecoveryInProgress() doesn't trigger an + * assertion failure. + */ + recoveryInProgress = RecoveryInProgress(); + START_CRIT_SECTION(); /* @@ -9665,7 +9673,7 @@ UpdateFullPageWrites(void) * Write an XLOG_FPW_CHANGE record. This allows us to keep track of * full_page_writes during archive recovery, if required. */ - if (XLogStandbyInfoActive() && !RecoveryInProgress()) + if (XLogStandbyInfoActive() && !recoveryInProgress) { XLogBeginInsert(); XLogRegisterData((char *) (&fullPageWrites), sizeof(bool));