diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 8dcdf5a764..e581488d57 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -468,7 +468,7 @@ typedef struct XLogCtlData
 	XLogRecPtr	lastSegSwitchLSN;
 
 	/* These are accessed using atomics -- info_lck not needed */
-	pg_atomic_uint64 logInsertResult;	/* last byte + 1 inserted to buffers */
+	pg_atomic_uint64 logInsertResult pg_attribute_aligned(8);	/* last byte + 1 inserted to buffers */
 	pg_atomic_uint64 logWriteResult;	/* last byte + 1 written out */
 	pg_atomic_uint64 logFlushResult;	/* last byte + 1 flushed */