Re: pg_stat_statements: calls under-estimation propagation

On 30.12.2012 08:31, Daniel Farina wrote:
> A version implementing that is attached, except I generate an
> additional 64-bit session not exposed to the client to prevent even
> casual de-leaking of the session state.  That may seem absurd, until
> someone writes a tool that de-xors things and relies on it and then
> nobody feels inclined to break it.  It also keeps the public session
> number short.
>
> I also opted to save the underestimate since I'm adding a handful of
> fixed width fields to the file format anyway.

This patch needs documentation. At a minimum, the new calls_underest 
field needs to be listed in the description of the pg_stat_statements.

Pardon for not following the discussion: What exactly does the 
calls_underest field mean? I couldn't decipher it from the patch. What 
can an admin do with the value? How does it compare with just bumping up 
pg_stat_statements.max?

- Heikki