* Jeff Janes: > Does the kernel really read a data block from disk into memory in > order to immediately overwrite it? I would have thought it would > optimize that away, at least if the writes are sized and aligned to > 512 or 1024 bytes blocks (which WAL should be).
With Linux, you'd have to use O_DIRECT to get that effect (but don't do that), otherwise writes happen in page size granularity, writing in 512 or 1024 byte blocks should really trigger a read-modify-write cycle. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
