Re: OEM reporting listener down but listener not actually down

  • From: Mladen Gogala <gogala.mladen@xxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Sun, 1 Dec 2019 19:32:46 -0500

Hi Jack,

That can also be a problem with DNS or a network route. If the host hosting the OEM cannot reach listener for whatever reason, you will get this error. It can be something as trivial as a bad port on the switch or change in DNS server.

Regards

On 12/1/19 7:19 PM, Jack van Zanen wrote:

intermittently we get some alert from OEM about listener being down.

Target name=*LISTENER_SCAN3_telstraexa1-000_1* <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2FNSW-ATP-GRID.snl.7net.com.au%3A7799%2Fem%2Fredirect%3FpageType%3DTARGET_HOMEPAGE%26targetName%3DLISTENER_SCAN3_telstraexa1-000_1%26targetType%3Doracle_listener&data=01%7C01%7CJVanZanen%40Seven.com.au%7C5514208b3d2848d8fe9f08d774d613ee%7Cb359291241554399b790752c894d2935%7C0&sdata=Pww2ktObyuQu4vBRxuWvcmAGkXXJIozv%2F8nHJP1ABHE%3D&reserved=0>
Categories=*Availability*
Message=*The listener is down: TNS-12545: Connect failed because target host or object does not exist .* <https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2FNSW-ATP-GRID.snl.7net.com.au%3A7799%2Fem%2Fredirect%3FpageType%3Dsdk-core-event-console-detailEvent%26issueID%3DE43696ECA26F42148CCCD6EC4862F4A9&data=01%7C01%7CJVanZanen%40Seven.com.au%7C5514208b3d2848d8fe9f08d774d613ee%7Cb359291241554399b790752c894d2935%7C0&sdata=z%2FQDPTS5qbEkx1MB8kdz3JKvyYGToJ4%2BUbcptqfRc7I%3D&reserved=0>


Checking the server we see no issue with the listener being down.


grid      24040      1  0 Nov23 ?        00:03:48 /u01/app/12.2.0.1/grid/bin/tnslsnr <http://12.2.0.1/grid/bin/tnslsnr> ASMNET1LSNR_ASM -no_crs_notify -inherit
grid      24402      1  0 Nov23 ?        00:04:58 /u01/app/12.2.0.1/grid/bin/tnslsnr <http://12.2.0.1/grid/bin/tnslsnr> LISTENER -no_crs_notify -inherit
grid     234773      1  0 Nov23 ?        00:02:16 /u01/app/12.2.0.1/grid/bin/tnslsnr <http://12.2.0.1/grid/bin/tnslsnr> LISTENER_SCAN2 -no_crs_notify -inherit
grid     234791      1  0 Nov23 ?        00:02:13 /u01/app/12.2.0.1/grid/bin/tnslsnr <http://12.2.0.1/grid/bin/tnslsnr> LISTENER_SCAN3 -no_crs_notify -inherit


This is Oracle 12.2 on Exadata Cloud at Customer solution . Anyone else seen this behaviour before?

Oracle suggested to turn on client and server sql net tracing but I am a bit hesitant due to the sheer volume of tracing it will likely generate before I get the issue again.

To me it looks like a DNS issue, but Oracle looked at this and there is no issues there.




Jack van Zanen


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Mladen Gogala
Database Consultant
Tel: (347) 321-1217

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