RE: minimizing pg_stat_statements performance overhead

Hello Raymond,

>> Sure, it definitely makes sense to reduce the overhead when the extension is disabled. I wanted to understand the
sourceof performance issue, and your explanations where not enough for reproducing it.
 
> Thanks again Fabien. I am attaching the patch to this email in the hope of getting it approved during the next commit
fest.
> I will continue trying to find a simple performance test to exemplify the performance degradation that I have seen
withmore complex workloads.
 

Patch applies and compiles cleanly. Global and local make check ok.

The patch adds an early exit in one of the hook when pgss is not enabled 
on a given query. This seems to be a long time oversight of some earlier 
additions which only had some (small or large depending) performance 
impact.

About the comment "...and" -> "... and" (add a space)

Otherwise all is well.

-- 
Fabien.