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
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