On 3 March 2018 at 00:30, Darafei "Komяpa" Praliaskouski <m...@komzpa.net> wrote:
> I gave this all some thought and it looks like it all could have not > happened if Postgres was able to cluster heap insertions by (id, ts) index. > We're ok with synchronuous_commit=off, so amplified write won't immediately > hit disk and can get cooled down in progress. Clustering doesn't require > perfect sorting: we need to minimize number of pages fetched, it's ok if > the pages are not consecutive on disk. > I'm surprised nobody has mentioned BRIN yet. Ever since BRIN was introduced, I've thought it would be very interesting to use it + the freespace map for coarse-grained tuple routing in heap inserts. Try to find the best-match range with BRIN and look for free space there. I think there was discussion of this early on, so you may want to look up the BRIN threads. The main challenge probably comes when a range is exhausted. Your writes would start spilling over into new heap pages and get intermixed again. Some support for pre-allocating new ranges would be needed. -- Craig Ringer http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
