On Mon, 2009-07-06 at 17:54 +0900, Fujii Masao wrote: > According to the result, using sync_file_range instead of fdatasync > has little effect in the performance of postgres.
["...when flushing XLOG"] Why did you think it would? AFAICS the range of dirty pages will be restricted to a fairly tight range anyway. The only difference between the two would indicate an OS inefficiency. I don't see an opportunity for XLOG to be more efficient by using a finer-grained API. I think there is still a valid use for sync_file_range at checkpoint, since the for some large tables this could reduce the number of pages needing to be written at checkpoint time. That would help smooth out larger writes. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
