Re: read_only_open_delayed

It has occurred to me that I saw a bug note a few months ago about FOB allocation in the DGA. I can't find it now (and I wasn't looking for it before so I don't know why it showed up). It might be worth checking immediately after startup if there are any unusual wait events or activity stats or latch operations that might be related to FOB or DGA.
There's a parameter _fob_dgalloc (default true) which might be relevant - but it's been around since 12.2 so if your timing problem only appeared in a recent upgrade then it's probably not connected.

Regards
Jonathan Lewis

On Tue, 5 Apr 2022 at 00:54, Fairlie Rego <fairlie.rego_at_gmail.com> wrote:

> Hi all,
>
> I have a 19.10 database with a large number of read only files which takes
> 21 minutes to open in production when a database switchover happens.
> Unfortunately this does not meet our RTO and we have tested the
> switchover/open with the read_only_open_delayed parameter in a test
> environment which is not an exact prod replica but as close to it as
> possible.
>
> So in the test environment the open time reduces from 8 minutes to 22
> seconds.
>
> SQL> select enabled,count(*) from v$datafile group by enabled;
>
> ENABLED COUNT(*)
> ---------- ----------
> READ ONLY 1091
> READ WRITE 496
>
> Keen to understand if anyone else is using this since this parameter has
> been around since 10.1
>
> Cheers
>
> --
> Fairlie Rego
> Executive Database Architect
> www.technoconsulting.com.au
> http://www.linkedin.com/in/fairlierego
> https://fairlierego.wordpress.com/
>
> Twitter _at_fairlierego
>

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