Re: [rfc] overhauling pgstat.stat

>
>
> we very successfully use a tmpfs volume for pgstat files (use a backport
> of multiple statfiles from 9.3 to 9.1

It works quite well as long as you have the objects (tables, indexes,
functions) spread across multiple databases. Once you have one database
with very large number of objects, tmpfs is not as effective.

It's going to help with stats I/O, but it's not going to help with high
CPU usage (you're reading and parsing the stat files over and over) and
every rewrite creates a copy of the file. So if you have 400MB stats,
you will need 800MB tmpfs + some slack (say, 200MB). That means you'll
use ~1GB tmpfs although 400MB would be just fine. And this 600MB won't
be used for page cache etc.

OTOH, it's true that if you have that many objects, 600MB of RAM is not
going to help you anyway.

Tomas

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