On Mon, Mar 18, 2013 at 5:52 PM, Bruce Momjian <br...@momjian.us> wrote: > With a potential 10-20% overhead, I am unclear who would enable this at > initdb time.
For what it's worth I think cpu overhead of the checksum is totally a red herring.. Of course there's no reason not to optimize it to be as fast as possible but if we say there's a 10% cpu overhead due to calculating the checksum users will think that's perfectly reasonable trade-off and have no trouble looking at their cpu utilization and deciding whether they have that overhead to spare. They can always buy machines with more cores anyways. Added I/O overhead, especially fsync latency is the performance impact that I think we should be focusing on. Uses will be totally taken by surprise to hear that checksums require I/O. And fsync latency to the xlog is very very difficult to reduce. You can buy more hard drives until the cows come home and the fsync latency will hardly change. -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
