Thank you, Craig, your answers are always insightful
> What is read_cluster() ? Are you talking about some kind of async and/or
I meant that if you want to read a chunk of data from file you (1)
might not call traditional fseek but rather memorize hard drive
cluster numbers to boost disk seeks and, (2) perform the read of disk
cluster directly.
> 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
>