Re: Application performance hit when performing archived log backups

On 2016/05/16 12:46, Ryan January wrote:

> Poking through ASH data the only commonality I found was an increase in system IO, which ultimately ended up being RMAN. We were performing very simple archived log backups via rman with a parallelism of 4. Backup sets are being pushed uncompressed across a 1Gb link to DataDomain mounted via NFS.
> App call times went from 1s normally to over 30s at their worst. Backing that parallelism off to 1 resulted in a smaller spike with an increased duration. Application performance falls off very sharply as the backup begins, with a slower 2-3 minute exponential increase in performance as the backup completes. The same execution plan has been verified for frequent SQL statements during both good and bad times.
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> Short of that, has anyone seen similar behavior? I would have never anticipated archived log backups to have this impact, but the timing matches up perfectly with 100% repeatability. If not the root cause, it's at least a contributor that we've identified as a fact. I would appreciate any suggestions of where we should consider continuing our troubleshooting, or guidance on what metrics we should gather.

Possible you're hitting BUG 17797438 (V$RMAN_STATUS query slow)? I've had that inconsistently across a few databases on 11.2.0.3...

Rich

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