Re: Catalog bloat (again)

On 01/27/2016 03:37 PM, Ivan Voras wrote:
>
>
> On 28 January 2016 at 00:13, Bill Moran <wmoran@potentialtech.com
> <mailto:wmoran@potentialtech.com>> wrote:
>
>     On Wed, 27 Jan 2016 23:54:37 +0100
>     Ivan Voras <ivoras@gmail.com <mailto:ivoras@gmail.com>> wrote:
>
>     > So, question #1: WTF? How could this happen, on a regularly vacuumed
>     > system? Shouldn't the space be reused, at least after a VACUUM? The issue
>     > here is not the absolute existence of the bloat space, it's that it's
>      > constantly growing for *system* tables.
>
>     With a lot of activity, once a day probably isn't regular enough.
>
>
> I sort of see what you are saying. I'm curious, though, what goes wrong
> with the following list of expectations:
>
>  1. Day-to-day load is approximately the same
>  2. So, at the end of the first day there will be some amount of bloat
>  3. Vacuum will mark that space re-usable
>  4. Within the next day, this space will actually be re-used
>  5. ... so the bloat won't grow.
>
> Basically, I'm wondering why is it growing after vacuums, not why it
> exists in the first place?

If something is causing the autovacuum to be aborted you can have this
problem.

JD


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