Re: Queries Per Second (QPS)

On Sat, Sep 26, 2015 at 11:06 PM, Guillaume Lelarge <guillaume(at)lelarge(dot)info>
wrote:

> Le 27 sept. 2015 8:02 AM, "Guillaume Lelarge" <guillaume(at)lelarge(dot)info> a
> écrit :
> >
> > Le 26 sept. 2015 6:26 PM, "Adam Scott" <adam(dot)c(dot)scott(at)gmail(dot)com> a
> écrit :
> > >
> > > How do we measure queries per second (QPS), not transactions per
> second, in PostgreSQL without turning on full logging which has a
> performance penalty and can soak up lots of disk space?
> > >
> >
> > The only way I can think of is to write an extension that will execute
> some code at the end of the execution of a query.
> >
> > Note that this might get tricky. Do you want to count any query? Such as
> those in explicit transactions and those in plpgsql functions? People might
> not see this your way, which may explain why I don't know of any such
> extension.
> >
>
> Thinking about this, such an extension already exists. It's
> pg_stat_statements. You need to sum the count column of the
> pg_stat_statements from time to time. The difference between two sums will
> be your number of queries.
>

That is what I was thinking, but the pg_stat_statement does discard
statements sometimes, discarding the counts with them. You would have set
pg_stat_statements.max to a higher value than you ever expect to get
reached.

Cheers,

Jeff