Scott, regardless of operating system support for DMA, an application may not benefit from it if it doesn't use appropriate system calls.
PostgreSQL is implemented mostly in C, so I do not know whether it needs to use special procedure calls, however this is true, for example, for Java http://www.ibm.com/developerworks/library/j-zerocopy/ 2011/9/9 Scott Marlowe <scott.marl...@gmail.com>: > On Fri, Sep 9, 2011 at 11:55 AM, Antonio Rodriges <antonio....@gmail.com> > wrote: >> Hello, >> >> Does anyone know whether PostgreSQL uses DMA (Direct Memory Access) in >> certain cases to improve networking IO performance? >> >> I mean "simple" query is which doesn't require any CPU processing, for ex >> SELECT column_a FROM table_b WHERE date = "2001-10-05" >> >> I need this to devise the best logic for the system with PostgreSQL as >> a layer. Certainly I could study PostgreSQL sources or test it with a >> simple application but I hope PostgreSQL experts are aware of this >> feature. > > That's all up to your hardware and OS, not postgresql > -- Kind regards, Antonio Rodriges -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
