Hi, On Thu, Jun 13, 2024 at 04:59:50PM +0900, Michael Paquier wrote: > Hi all, > > 2) Make the shmem pgstats pluggable so as it is possible for extensions > to register their own stats kinds.
Thanks for the patch! I like the idea of having custom stats (it has also been somehow mentioned in [1]). > 2) is actually something that can be used for more things than > just pg_stat_statements, because people love extensions and > statistics (spoiler: I do). +1 > * Making custom stats data persistent is an interesting problem, and > there are a couple of approaches I've considered: > ** Allow custom kinds to define callbacks to read and write data from > a source they'd want, like their own file through a fd. This has the > disadvantage to remove the benefit of c) above. > ** Store everything in the existing stats file, adding one type of > entry like 'S' and 'N' with a "custom" type, where the *name* of the > custom stats kind is stored instead of its ID computed from shared > memory. What about having 2 files? - One is the existing stats file - One "predefined" for all the custom stats (so what you've done minus the in-core stats). This one would not be configurable and the extensions will not need to know about it. Would that remove the benefit from c) that you mentioned up-thread? [1]: https://www.postgresql.org/message-id/20220818195124.c7ipzf6c5v7vxymc%40awork3.anarazel.de Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
