Re: postgresql latency & bgwriter not doing its job

On Thu, Sep 4, 2014 at 12:36 AM, Andres Freund <andres@2ndquadrant.com> wrote:
> It's imo quite clearly better to keep it allocated. For one after
> postmaster started the checkpointer successfully you don't need to be
> worried about later failures to allocate memory if you allocate it once
> (unless the checkpointer FATALs out which should be exceedingly rare -
> we're catching ERRORs). It's much much more likely to succeed
> initially. Secondly it's not like there's really that much time where no
> checkpointer isn't running.

In principle you could do the sort with the full sized array and then
compress it to a list of buffer IDs that need to be written out. This
way most of the time you only need a small array and the large array
is only needed for a fraction of a second.

Regards,
Ants Aasma
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