On 24/09/2011 2:49 PM, Antonio Rodriges wrote:
Hello, It is interesting how PostgreSQL reads the tablefiie. Whether its indexes store/use filesystem clusters locations containing required data (so it can issue a low level cluster read) or it just fseeks inside a file?
What is read_cluster() ? Are you talking about some kind of async and/or direct I/O? If so, PostgreSQL is not designed for direct I/O, it benefits from using the OS's buffer cache, I/O scheduler, etc.
IIRC Pg uses pread() to read from its data files, but I didn't go double check in the sources to make sure.
-- Craig Ringer -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
