Re: Re: pg_stat_statements normalisation without invasive changes to the parser (was: Next steps on pg_stat_statements normalisation)

Peter Geoghegan <peter(at)2ndquadrant(dot)com> writes:
> Having taken another look at the code, I wonder if we wouldn't have
> been better off just fastpathing out of pgss_store in the first call
> (in a pair of calls made by a backend as part an execution of some
> non-prepared query) iff there is already an entry in the hashtable -
> after all, we're now going to the trouble of acquiring the spinlock
> just to increment the usage for the entry by 0 (likewise, every other
> field), which is obviously superfluous. I apologise for not having
> spotted this before submitting my last patch.

On reflection, we can actually make the code a good bit simpler if
we push the responsibility for initializing the usage count correctly
into entry_alloc(), instead of having to fix it up later. Then we
can just skip the entire adjust-the-stats step in pgss_store when
building a sticky entry. See my commit just now.

regards, tom lane