4 Commits (5ffbbcfa160b2e689dfb0542dfdbc4e16fc0dec9)

Author	SHA1	Message	Date
Tom Lane	f3fa31327e	Add pg_buffercache_usage_counts() to contrib/pg_buffercache. ... It was pointed out that pg_buffercache_summary()'s report of the overall average usage count isn't that useful, and what would be more helpful in many cases is to report totals for each possible usage count. Add a new function to do it like that. Since pg_buffercache 1.4 is already new for v16, we don't need to create a new extension version; we'll just define this as part of 1.4. Nathan Bossart Discussion: https://postgr.es/m/20230130233040.GA2800702@nathanxps13	3 years ago
Andres Freund	2589434ae0	pg_buffercache: Add pg_buffercache_summary() ... Using pg_buffercache_summary() is significantly cheaper than querying pg_buffercache and summarizing in SQL. Author: Melih Mutlu <m.melihmutlu@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Aleksander Alekseev <aleksander@timescale.com> Reviewed-by: Zhang Mingli <zmlpostgres@gmail.com> Discussion: https://postgr.es/m/CAGPVpCQAXYo54Q%3D8gqBsS%3Du0uk9qhnnq4%2B710BtUhUisX1XGEg%40mail.gmail.com	3 years ago
Robert Haas	a448e49bcb	Revert 56-bit relfilenode change and follow-up commits. ... There are still some alignment-related failures in the buildfarm, which might or might not be able to be fixed quickly, but I've also just realized that it increased the size of many WAL records by 4 bytes because a block reference contains a RelFileLocator. The effect of that hasn't been studied or discussed, so revert for now.	3 years ago
Robert Haas	05d4cbf9b6	Increase width of RelFileNumbers from 32 bits to 56 bits. ... RelFileNumbers are now assigned using a separate counter, instead of being assigned from the OID counter. This counter never wraps around: if all 2^56 possible RelFileNumbers are used, an internal error occurs. As the cluster is limited to 2^64 total bytes of WAL, this limitation should not cause a problem in practice. If the counter were 64 bits wide rather than 56 bits wide, we would need to increase the width of the BufferTag, which might adversely impact buffer lookup performance. Also, this lets us use bigint for pg_class.relfilenode and other places where these values are exposed at the SQL level without worrying about overflow. This should remove the need to keep "tombstone" files around until the next checkpoint when relations are removed. We do that to keep RelFileNumbers from being recycled, but now that won't happen anyway. However, this patch doesn't actually change anything in this area; it just makes it possible for a future patch to do so. Dilip Kumar, based on an idea from Andres Freund, who also reviewed some earlier versions of the patch. Further review and some wordsmithing by me. Also reviewed at various points by Ashutosh Sharma, Vignesh C, Amul Sul, Álvaro Herrera, and Tom Lane. Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com	3 years ago