Hello
While looking at slow queries on pg_stat_statements. I was looking for percentile fields.. If we are worried about CPU cost, maybe it could be useful to turn in on when you have a high stddev_exec_time for the query ? Regards, ________________________________ De : Adrien Nayrat <adrien.nay...@anayrat.info> Envoyé : samedi 2 novembre 2019 10:23:49 À : Tomas Vondra; Igor Calabria Cc : pgsql-hack...@postgresql.org Objet : Re: Adding percentile metrics to pg_stat_statements module On 10/31/19 8:32 PM, Tomas Vondra wrote: > IMO having some sort of CDF approximation (being a q-digest or t-digest) > would be useful, although it'd probably need to be optional (mostly > becuase of memory consumption). +1, I like this idea. If we are afraid of CPU cost we could imagine some kind of sampling or add the possibility to collect only for a specific queryid. I dreamed of this kind of feature for PoWA. Thus, it could make possible to compare CDF between two days for example, before and after introducing a change. Regards, -- Adrien NAYRAT
