Tom Lane escribió: > Alvaro Herrera <alvhe...@commandprompt.com> writes: > > Maybe it would make more sense to try to reorder the fsync calls > > instead. > > Reorder to what, though? You still have the problem that we don't know > much about the physical layout on-disk.
Well, to block numbers as a first step. However, this reminds me that sometimes we take the block-at-a-time extension policy too seriously. We had a customer that had a performance problem because they were inserting lots of data to TOAST tables, causing very frequent extensions. I kept wondering whether an allocation policy that allocated several new blocks at a time could be useful (but I didn't try it). This would also alleviate fragmentation, thus helping the physical layout be more similar to logical block numbers. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
