Re: Vacuum: allow usage of more than 1GB of work mem - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Vacuum: allow usage of more than 1GB of work mem
Date
Msg-id CA+Tgmob6A=hrut0Fg8LHpY8U70jd5fKutiVCPaaMhHF9-T2S+g@mail.gmail.com
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In response to Re: Vacuum: allow usage of more than 1GB of work mem  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Vacuum: allow usage of more than 1GB of work mem  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
On Tue, Sep 6, 2016 at 2:16 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> What occurs to me is that we can exactly predict how many tuples we
> are going to get when we autovacuum, since we measure that and we know
> what the number is when we trigger it.
>
> So there doesn't need to be any guessing going on at all, nor do we
> need it to be flexible.

No, that's not really true.  A lot can change between the time it's
triggered and the time it happens, or even while it's happening.
Somebody can run a gigantic bulk delete just after we start the
VACUUM.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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