On Thu, 2008-10-30 at 09:46 +0900, Koichi Suzuki wrote: > I'm not sure if blocks reffered from all WAL records in single WAL > segment can fit kernel cache. This is why current pg_readahead > returns the last LSN and require starting LSN. So far, with FPW, it > seems that we can prefetch all the pages in a WAL segment. So it > will be okay for archive log compressed with pg_compresslog. I'll > test if it's okay in the case full_page_writes=off.
I'd prefer to be able to specify max_readahead_pages than have to control things at a micro level like that. If you have lots of memory you can set that higher. > Anyway, I'd like to keep my proposal for 8.4 and continue the test and > evaluation to report to the mailing list. > > I'll also change the whole code to run in the core. OK, I quite liked the idea of a separate program. That allows it to work with 8.3 as well as 8.4. No problem with it being in core at all. As ever, good thinking, good patch. -- 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
