Hello,
I've got this 2 node RAC 11.2.0.4 and an app (actually 3 app servers)
which is realy rac unfriendly.
There is a table 'clusternode' with 3 rows (64kb = 8 blocks) and ever
1-3 sec there is an update run on one of the rac node:
update clusternode set lastheartbeat = sysdate where clusterid =
'oneOftheStringwitClusterId' .
Normaly this query takes 8 li/o and takes below 1sec it is doing full
table scan (there is no index on clusteridand Full table scan is the
only possible plan).
But out of nothing it can take ~30 sec (but still 8 logical i/o) and the
app is hanging, during that time I can see 'gc current block busy' .
It is 11.2.0.4 and the odd thing is I can not see any interconnect
activity on AWR during the time of the issue (seems like a bug to me).
Is there any way to mitigate such behaviour, my current thoughts:
- node affinity via singleton service
- shutdown 1 rac node and run on 1 node only
- make this table pctfeee 99 ?
Any other ideas ?
Regards.
Greg
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