st 12. 5. 2021 v 9:13 odesÃlatel Julien Rouhaud <rjuju...@gmail.com> napsal:
> On Wed, May 12, 2021 at 08:58:45AM +0200, Pavel Stehule wrote: > > > > I don't like the idea of implicit force enabling any feature flag, but it > > is better than current design. But it doesn't look like a robust > solution. > > > > Does it mean that if somebody disables computed_query_id, then > > pg_stat_statements will not work? > > It depends, but if you mean "setting up pg_stat_statements, intentionally > disabling in-core queryid calculation and not configuring an alternative > source" then yes pg_stat_statements will not work. But I don't see any > difference from "someone reduce wal_level and complain that replication > does > not work" or "someone disable fsync and complain that data got > corrupted". We > provide a sensible default configuration, you can mess it up if you don't > know > what you're doing. > > > Why is there the strong dependency between computed_query_id and > > pg_stat_statements? Can this dependency be just optional? > > Once again no, as it otherwise would mean that postgres unilaterally > decides > that pg_stat_statements' approach to compute a query identifier is the one > and > only ultimate truth and nothing else could be useful for anyone. > ok. Understand. If I understand well, then computed_query_id does not make sense for pg_stat_statemenst, because this extension always requires it. Cannot be better to use queryid inside pg_stat_statements every time without dependency on computed_query_id? And computed_query_id can be used only for EXPLAIN and for pg_stat_activity. pg_stat_statements cannot work without a queryid, so is useless to speak about configuration. If you use pg_stat_statements, then the queryid will be computed every time, but the visibility will be only for pg_stat_statements. Or a different strategy. I understand so computed_query_id should be active. But I dislike the empty result of pg_stat_statements when computed_query_id is off. Is it possible to raise an exception instead of showing an empty result? The most correct fix from my perspective is just check in function pg_stat_statements if query id is computed or not. If not, and there is no data, then raise an exception with the hint "enable compute_query_id". When there is data, then show a warning with the mentioned hint and show data. What do you think about it? Pavel
