From: Fujii Masao <fujii@postgresql.org>
Date: Thu, 20 Apr 2017 14:12:57 +0000 (+0900)
Subject: Don't call the function that may raise an error while holding spinlock.
X-Git-Tag: REL_10_BETA1~220
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8bbc618b4825b13a9776f2289acd06483e140300;p=thirdparty%2Fpostgresql.git

Don't call the function that may raise an error while holding spinlock.

It's not safe to raise an error while holding spinlock. But previously
logical replication worker for table sync called the function which
reads the system catalog and may raise an error while it's holding
spinlock. Which could lead to the trouble where spinlock will never
be released and the server gets stuck infinitely.

Author: Petr Jelinek
Reviewed-by: Kyotaro Horiguchi and Fujii Masao
Reported-by: Fujii Masao
Discussion: http://postgr.es/m/CAHGQGwFDWh_Qr-q_GEMpD+qH=vYPMdVqw=ZOSY3kX_Pna9R9SA@mail.gmail.com
---

diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 108326bef1c..b4b48d92cf4 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -705,17 +705,20 @@ LogicalRepSyncTableStart(XLogRecPtr *origin_startpos)
 {
 	char		   *slotname;
 	char		   *err;
+	char		relstate;
+	XLogRecPtr	relstate_lsn;
 
 	/* Check the state of the table synchronization. */
 	StartTransactionCommand();
+	relstate = GetSubscriptionRelState(MyLogicalRepWorker->subid,
+									   MyLogicalRepWorker->relid,
+									   &relstate_lsn, false);
+	CommitTransactionCommand();
+
 	SpinLockAcquire(&MyLogicalRepWorker->relmutex);
-	MyLogicalRepWorker->relstate =
-		GetSubscriptionRelState(MyLogicalRepWorker->subid,
-								MyLogicalRepWorker->relid,
-								&MyLogicalRepWorker->relstate_lsn,
-								false);
+	MyLogicalRepWorker->relstate = relstate;
+	MyLogicalRepWorker->relstate_lsn = relstate_lsn;
 	SpinLockRelease(&MyLogicalRepWorker->relmutex);
-	CommitTransactionCommand();
 
 	/*
 	 * To build a slot name for the sync work, we are limited to NAMEDATALEN -