Federation likes (votes) are wildly different from server to server as it stands now. And unless something is way off on my particular server, 0.4 seconds is what PostgreSQL is reporting as the mean (average) time per single comment vote INSERT, and post vote INSERT is similar. (NOTE: my server is classic hard drives, 100MB/sec bencharked, not a SSD)
Discussion of the SQL statement for a single comment vote insert: https://lemmy.ml/post/1446775
Every single VOTE is both a HTTP transaction from the remote server and a SQL transaction. I am looking into Postgress supporting batches of inserts to not check all the index constraints at each single insert: https://www.postgresql.org/docs/current/sql-set-constraints.html
Can the Rust code for inserts from federation be reasonably modified to BEGIN TRANSACTION only every 10th comment_like INSERT and then do a COMMIT of all of them at one time? and possibly a timer that if say 15 seconds passes with no new like entries from remote servers, do a COMMIT to flush based a timeout.
Storage I/O writing for votes alone is pretty large…
well tuned a single insert should take less than a tenth of a millisecond on postgresql. even with 10 indexes and a trigger 0.4 seconds is not how long an insert takes. if you’re seeing slow times it might be due to very different things, especially the huge locking hot_rank updates that make all inserts / updates on comments,posts table pause until done (which will show up as slower times in the query times you’re looking at)
I mixed up the units, but it is taking .4 milliseconds typically. I really want to get some of these stats out of the major servers (Beehaw, Lemmy.world, Lemmy.ml)