Re: Proposal : For Auto-Prewarm.

On Wed, Feb 22, 2017 at 4:06 AM, Peter Eisentraut
<peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:
> On 2/10/17 15:12, Robert Haas wrote:
>> Right. I can't see why you'd want to be able to separately control
>> those two things. If you're not dumping, you don't want to load; if
>> you're not loading, you don't want to dump.
>
> What about the case where you want to prewarm a standby from the info
> from the primary (or another standby)?

I think it's OK to treat that as something of a corner case. There's
nothing to keep you from doing that today: just use pg_buffercache to
dump a list of blocks on one server, and then pass those blocks to
pg_prewarm on another server. The point of this patch, AIUI, is to
automate a particularly common case of that, which is to dump before
shutdown and load upon startup. It doesn't preclude other things that
people want to do.

I suppose we could have an SQL-callable function that does an
immediate dump (without starting a worker). That wouldn't hurt
anything, and might be useful in a case like the one you mention.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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