On Tue, Oct 9, 2012 at 1:51 AM, Amit Kapila <amit.kap...@huawei.com> wrote: > On Monday, October 01, 2012 11:11 PM Jeff Davis wrote: >> On Mon, 2012-10-01 at 18:14 +0100, Simon Riggs wrote: >> > You are missing large parts of the previous thread, giving various >> > opinions on what the UI should look like for enabling checksums. >> >> I read through all of the discussion that I could find. There was quite >> a lot, so perhaps I have forgotten pieces of it. >> >> But that one section in the docs does look out of date and/or confusing >> to me. >> >> I remember there was discussion about a way to ensure that checksums are >> set cluster-wide with some kind of special command (perhaps related to >> VACUUM) and a magic file to let recovery know whether checksums are set >> everywhere or not. That doesn't necessarily conflict with the GUC though >> (the GUC could be a way to write checksums lazily, while this new >> command could be a way to write checksums eagerly). >> >> If some consensus was reached on the exact user interface, can you >> please send me a link? > > AFAICT complete consensus has not been reached but one of the discussions can > be found on below link: > http://archives.postgresql.org/pgsql-hackers/2012-03/msg00279.php > Here Robert has given suggestions and then further there is more discussion > based on that points. > > According to me, the main points where more work for this patch is required > as per previous discussions is as follows: > > 1. Performance impact of WAL log for hint-bits needs to be verified for > scenario's other than pg_bench (Such as bulk data load (which I > feel there is some way to optimize, but I don't know if that’s part of > this patch)).
Atri has a patch posted which (if it passes muster) would eliminate the i/o impact of WAL logging hint bits following a bulk load or any scenario where many pages worth of tuples were sequentially written out with the same XID. Atri's patch was written with the checksum patch in mind. http://archives.postgresql.org/message-id/CAOeZVid7zd9V-9WsEtf9wRCd0H4yw_1OgCLm7%3DCdvGPCxZcJJw%40mail.gmail.com merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
