Jonah H. Harris escribió: > On Mon, Dec 15, 2008 at 11:29 AM, Tom Lane <t...@sss.pgh.pa.us> wrote:
> > We don't really have an acceptable solution for the conflict with hint > > bit behavior. The shutdown issue is minor, agreed, but that's not the > > stumbling block. > > Agreed on the shutdown issue. But, didn't this patch address the hint > bit setting as discussed? After performing a cursory look at the > patch, it appears that hint-bit changes are detected and a WAL entry > is written on buffer flush if hint bits had been changed. I don't see > anything wrong with this in theory. Am I missing something? That only does heap hint bits, but it does nothing about pd_flags, the btree flags (btpo_cycleid I think), and something else I don't recall at the moment. This was all solvable however. The big problem with it was that it was using a new bit in pd_flags in unsafe ways. To make it safe you'd have to grab a lock on the page, which is very probably problematic. > Now, in the case where hint bits have been updated and a WAL record is > required because the buffer is being flushed, requiring the WAL to be > flushed up to that point may be a killer on performance. Has anyone > tested it? I didn't measure it but I'm sure it'll be plenty slow. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
