Greg Smith wrote: > One of the components to the write queue is some notion that writes that > have been waiting longest should eventually be flushed out. Linux has > this number called dirty_expire_centiseconds which suggests it enforces > just that, set to a default of 30 seconds. This is why some 5-minute > interval checkpoints with default parameters, effectively spreading the > checkpoint over 2.5 minutes, can work under the current design. > Anything you wrote at T+0 to T+2:00 *should* have been written out > already when you reach T+2:30 and sync. Unfortunately, when the system > gets busy, there is this "congestion control" logic that basically > throws out any guarantee of writes starting shortly after the expiration > time.
Should we be writing until 2:30 then sleep 30 seconds and fsync at 3:00? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
