Re: pg_multixact/members growing

On 2018-May-23, Tom Lane wrote:

> Tiffany Thang <tiffanythang(at)gmail(dot)com> writes:
> > Where do I find pg_controldata? I could not locate it on the file system.
>
> Hmm, should be one of the installed PG executables.
>
> > pg_clog/ or pg_subtrans/ or pg_multixact/offsets/ are getting larger too
> > but by only a few hundreds MBs.
>
> This is consistent with the idea that something is holding back the
> oldest-transaction horizon. (However, I'd think you'd also be having
> serious problems with table bloat if that were true, so it's a bit
> mystifying.) Did you check for unclosed prepared transactions?

Another option is that you have a standby server with
hot_standby_feedback enabled, and an open transaction there. I'm not
sure to what extent it is possible for that to cause multixact problems,
but it wouldn't hurt to check.

--
Álvaro Herrera https://www.2ndQuadrant.com/
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