Re: Properly initialize negative/empty cache entries in relfilenodemap

Hi,

On Thu, Aug 29, 2013 at 2:35 PM, MauMau <maumau307(at)gmail(dot)com> wrote:

>
> Great! Could anybody find the root cause for the following memory leak
> problem, and if possible, fix this?
>
> http://www.postgresql.org/**message-id/**214653D8DF574BFEAA6ED53E545E99**
> E4(at)maumau<http://www.postgresql.org/message-id/214653D8DF574BFEAA6ED53E545E99E4@maumau>
>
> Heiki helped to solve this and found that pg_statistic entries are left in
> CacheMemoryContext, but we have no idea where and how they are created and
> left. This seems difficult to me.
>
> VALGRIND won't help you for this one
You hit 2 issues
- user can create negative cache entries in pg_statistic with SELECT but
they are unbound (at first there was a LRU aging but it was removed in 2006)

- if there's no row in pg_statistic for a relation/column then
RemoveStatistics, called by DROP ..., doesn't invalidate the cache (which
should remove these negative entries).