Fix bogus time printout in walreceiver's debug log messages.

The displayed sendtime and receipttime were always exactly equal, because
somebody forgot that timestamptz_to_str returns a static buffer (thereby
simplifying life for most callers, at the cost of complicating it for those
who need two results concurrently).  Apply the same pstrdup solution used
by the other call sites with this issue.  Back-patch to 9.2 where the
faulty code was introduced.  Per bug #9849 from Haruka Takatsuka, though
this is not exactly his patch.

Possibly we should change timestamptz_to_str's API, but I wouldn't want
to do so in the back branches.

diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 43db10851c385fd71c80292462cae59e4cabe86a..b0de0ea253efaedd653b6fb5080ff15c15525f5a 100644 (file)
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -1199,9 +1199,19 @@ ProcessWalSndrMessage(XLogRecPtr walEnd, TimestampTz sendTime)
    SpinLockRelease(&walrcv->mutex);
 
    if (log_min_messages <= DEBUG2)
+   {
+       char       *sendtime;
+       char       *receipttime;
+
+       /* Copy because timestamptz_to_str returns a static buffer */
+       sendtime = pstrdup(timestamptz_to_str(sendTime));
+       receipttime = pstrdup(timestamptz_to_str(lastMsgReceiptTime));
        elog(DEBUG2, "sendtime %s receipttime %s replication apply delay %d ms transfer latency %d ms",
-            timestamptz_to_str(sendTime),
-            timestamptz_to_str(lastMsgReceiptTime),
+            sendtime,
+            receipttime,
             GetReplicationApplyDelay(),
             GetReplicationTransferLatency());
+       pfree(sendtime);
+       pfree(receipttime);
+   }
 }