Update comments in RecordTransactionCommit() to mention unlogged tables.

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 4ecf82d6a19af7b93a4a2d409ad07d40086246f7..1e31e07ec97510269676c2987bec4e0344c0eaf2 100644 (file)
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -1033,14 +1033,15 @@ RecordTransactionCommit(void)
         * Check if we want to commit asynchronously.  We can allow the XLOG flush
         * to happen asynchronously if synchronous_commit=off, or if the current
         * transaction has not performed any WAL-logged operation.  The latter case
-        * can arise if the current transaction wrote only to temporary tables.
-        * In case of a crash, the loss of such a transaction will be irrelevant
-        * since temp tables will be lost anyway.  (Given the foregoing, you might
-        * think that it would be unnecessary to emit the XLOG record at all in
-        * this case, but we don't currently try to do that.  It would certainly
-        * cause problems at least in Hot Standby mode, where the KnownAssignedXids
-        * machinery requires tracking every XID assignment.  It might be OK to
-        * skip it only when wal_level < hot_standby, but for now we don't.)
+        * can arise if the current transaction wrote only to temporary and/or
+        * unlogged tables.  In case of a crash, the loss of such a transaction
+        * will be irrelevant since temp tables will be lost anyway, and unlogged
+        * tables will be truncated.  (Given the foregoing, you might think that it
+        * would be unnecessary to emit the XLOG record at all in this case, but we
+        * don't currently try to do that.  It would certainly cause problems at
+        * least in Hot Standby mode, where the KnownAssignedXids machinery
+        * requires tracking every XID assignment.  It might be OK to skip it only
+        * when wal_level < hot_standby, but for now we don't.)
         *
         * However, if we're doing cleanup of any non-temp rels or committing any
         * command that wanted to force sync commit, then we must flush XLOG