On 2016-01-07 11:27:13 +0100, Fabien COELHO wrote: > I read your patch and I know what I want to try to have a small and simple > fix. I must admit that I have not really understood in which condition the > checkpointer would decide to close a file, but that does not mean that the > potential issue should not be addressed.
There's a trivial example: Consider three tablespaces and max_files_per_process = 2. The balancing can easily cause three files being flushed at the same time. But more importantly: You designed the API to be generic because you wanted it to be usable for other purposes as well. And for that it certainly needs to deal with that. > Also, I gave some thoughts about what should be done for bgwriter random > IOs. The idea is to implement some per-file sorting there and then do some > LRU/LFU combing. It would not interact much with the checkpointer, so for me > the two issues should be kept separate and this should not preclude changing > the checkpointer, esp. given the significant performance benefit of the > patch. Well, the problem is that the patch significantly regresses some cases right now. So keeping them separate isn't particularly feasible. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
