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.
>

and just idea - can we use a database for storing these files. It can be
used in unlogged tables. Second idea - hold a one bg worker as persistent
memory key value database and hold data in memory with some optimizations -
using anti cache and similar memory database fetures.

Pavel

>
> Tomas
>
>
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