Re: Protect syscache from bloating with negative cache entries

Hi,

On 2018-03-07 08:01:38 -0300, Alvaro Herrera wrote:
> I wonder if this is just because we refuse to acknowledge the notion of
> a connection pooler.  If we did, and the pooler told us "here, this
> session is being given back to us by the application, we'll keep it
> around until the next app comes along", could we clean the oldest
> inactive cache entries at that point?  Currently they use DISCARD for
> that.  Though this does nothing to fix hypothetical cache bloat for
> pg_dump in bug #14936.

I'm not seeing how this solves anything?  You don't want to throw all
caches away, therefore you need a target size.  Then there's also the
case of the cache being too large in a single "session".

Greetings,

Andres Freund