Re: tnsping times intermittently high

On Sun, 15 Jul 2007 02:01:11 GMT, "Gerald Sinkiewicz" <sinkiege_at_snet.net> wrote:

>A bit strange:
>
>1. tnsnames.ora uses host = ipaddress, not FQDNS names.
>2. tnsping from the box (AIX5L) to one alias on the same box comes back at
>times OK (10msec) at other times
>OK (19000msec) or more.
>It was high for a period of a couple of hours, then the problem went away,
>well was still on-and-off
>at high numbers, but mostly OK (0msec).
>3. tnsping to other tns aliases on the same box did not show degraded
>performance at anytime.
>4. there are about 15 distinct listeners on the box (actually it is an HA
>cluster of 2 boxes but not RAC) each has its own IP address and distinct
>port number.
>5. Only one of the listeners is showing this degradation, all the others are
>consistenly 10msec.
>6. Eventhough there are no DNS names in the tnsnames.ora file, the problem
>seems to have come from
>a reverse dns lookup than oracle TNS was doing. We found the primary DNS was
>having a slow time doing
>a reverse lookup of just this one IP Address (this time). The secondary DNS
>was not slow for the same
>reverse lookup. We fixed the problem with the slow connections and tnsping
>high by swapping primary and secondary
>DNS's.
>7. A similar issue has occured with the same primary DNS a few weeks back
>but no Oracle related. The victum then
>was a couple of mail hubs.
>
>So, why does tns do a reverse IP address lookup at all, it seems from our
>experience that it does?
>Maybe it is for its listener.log or something like that?
>Or am I thinking incorrectly (again)?
>

1 Your post doesn't have a version number, so no one will be capable to answer it correctly
2 I can't think of any reason to do tnsping on a structural basis. I'm not sure why you believe you constantly need to execute tnsping 3 I also can't think of any reason to have 15 listeners on a server. 4 Oracle has always recommended against using hardcoded IP addresses 5 As far as I know tnsping doesn't do a reverse lookup, but why don't you enable tnsping tracing (tnsping.trace_level = 16 in sqlnet.ora) before posting a bunch of wild guesses.

I would recommend discontinue to use tnsping on a structural basis, this will also result in the 'problem' going away automatically.

-- 
Sybrand Bakker
Senior Oracle DBA