-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Tom Lane wrote: > Gregory Stark <[EMAIL PROTECTED]> writes: >> Recently there was a post on -performance about a particular case where >> Postgres doesn't make very good use of the I/O system. This is when you try >> to >> fetch many records spread throughout a table in random order. > >> http://archives.postgresql.org/pgsql-performance/2007-12/msg00005.php > > Since the OP in that thread has still supplied zero information > (no EXPLAIN, let alone ANALYZE, and no version info), it's pure > guesswork as to what his problem is. Nonetheless, asynchronous IO will reap performance improvements. Wether a specific case would indeed benefit from it is imho irrelevant, if other cases can indeed be found, where performance would be improved significantly.
I experimented with a raid of 8 solid state devices, and found that the blocks/second for random access improved signifacantly with the number of processes doing the access. I actually wanted to use said raid as a tablespace for postgresql, and alas, the speedup did not depend on the number of drives in the raid, which is very unfortunate. I still got the lower solid-state latency, but the raid did not help. Regards, Jens-Wolfhard Schicke -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFHUwM7zhchXT4RR5ARAsziAJ9qm/c8NuaJ+HqoJo9Ritb2t92fRwCgnF9J r5YU/Fa0mNYG7YXed4QW7K4= =Mvyj -----END PGP SIGNATURE----- ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate