2 files changed, 17 insertions, 7 deletions
diff --git a/src/backend/access/spgist/spgdoinsert.c b/src/backend/access/spgist/spgdoinsert.c
index 1fd331cbdfd..9f425ca3558 100644
--- a/src/backend/access/spgist/spgdoinsert.c
+++ b/src/backend/access/spgist/spgdoinsert.c
@@ -1946,9 +1946,12 @@ spgdoinsert(Relation index, SpGistState *state,
 			 * Attempt to acquire lock on child page.  We must beware of
 			 * deadlock against another insertion process descending from that
 			 * page to our parent page (see README).  If we fail to get lock,
-			 * abandon the insertion and tell our caller to start over.  XXX
-			 * this could be improved; perhaps it'd be worth sleeping a bit
-			 * before giving up?
+			 * abandon the insertion and tell our caller to start over.
+			 *
+			 * XXX this could be improved, because failing to get lock on a
+			 * buffer is not proof of a deadlock situation; the lock might be
+			 * held by a reader, or even just background writer/checkpointer
+			 * process.  Perhaps it'd be worth retrying after sleeping a bit?
 			 */
 			if (!ConditionalLockBuffer(current.buffer))
 			{
diff --git a/src/backend/access/spgist/spginsert.c b/src/backend/access/spgist/spginsert.c
index f4d0fe5a0c2..2a50d87c74b 100644
--- a/src/backend/access/spgist/spginsert.c
+++ b/src/backend/access/spgist/spginsert.c
@@ -45,10 +45,17 @@ spgistBuildCallback(Relation index, HeapTuple htup, Datum *values,
 	/* Work in temp context, and reset it after each tuple */
 	oldCtx = MemoryContextSwitchTo(buildstate->tmpCtx);
 
-	/* No concurrent insertions can be happening, so failure is unexpected */
-	if (!spgdoinsert(index, &buildstate->spgstate, &htup->t_self,
-					 *values, *isnull))
-		elog(ERROR, "unexpected spgdoinsert() failure");
+	/*
+	 * Even though no concurrent insertions can be happening, we still might
+	 * get a buffer-locking failure due to bgwriter or checkpointer taking a
+	 * lock on some buffer.  So we need to be willing to retry.  We can flush
+	 * any temp data when retrying.
+	 */
+	while (!spgdoinsert(index, &buildstate->spgstate, &htup->t_self,
+						*values, *isnull))
+	{
+		MemoryContextReset(buildstate->tmpCtx);
+	}
 
 	MemoryContextSwitchTo(oldCtx);
 	MemoryContextReset(buildstate->tmpCtx);