On Wed, Oct 5, 2022 at 5:19 AM Andres Freund <and...@anarazel.de> wrote:
> > I light dusted off my old varint implementation from [1] and converted the > RelFileLocator and BlockNumber from fixed width integers to varint ones. This > isn't meant as a serious patch, but an experiment to see if this is a path > worth pursuing. > > A run of installcheck in a cluster with autovacuum=off, full_page_writes=off > (for increased reproducability) shows a decent saving: > > master: 241106544 - 230 MB > varint: 227858640 - 217 MB > > The average record size goes from 102.7 to 95.7 bytes excluding the remaining > FPIs, 118.1 to 111.0 including FPIs. > I have also executed my original test after applying these patches on top of the 56 bit relfilenode patch. So earlier we saw the WAL size increased by 11% (66199.09375 kB to 73906.984375 kB) and after this patch now the WAL generated is 58179.2265625. That means in this particular example this patch is reducing the WAL size by 12% even with the 56 bit relfilenode patch. [1] https://www.postgresql.org/message-id/CAFiTN-uut%2B04AdwvBY_oK_jLvMkwXUpDJj5mXg--nek%2BucApPQ%40mail.gmail.com -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
