Re: Filesystems WAS: Perfomance Tuning

Greg,

> FWIW, Informix can be run using a "cooked" (Unix) file for storing data or
> it uses "raw" disk space and bypasses the ordinary (high level) UNIX
> controllers and does its own reads/writes. About 10 times faster and safer.
> Of course, itmay have taken a lot of programmer time to make that solid.
> But the performance gains are significant.

Yes, but it's still slower than PostgreSQL on medium-end hardware. ;-)

This idea has been discussed numerous times on the HACKERS list, and is a
(pretty much) closed issue. While Oracle and SQL Server use their own
filesystems, PostgreSQL will not because:

1) It would interfere with our cross-platform compatibility. PostgreSQL runs
on something like 20 OSes.

2) The filesystem projects out there are (mostly) well-staffed and are
constantly advancing using specialized technology and theory. There's no way
that the PostgreSQL team can do a better job in our "spare time".

3) Development of our "own" filesystem would then require PostgreSQL to create
and maintain a whole hardware compatibility library, and troubleshoot
problems on exotic hardware and wierd RAID configurations.

4) A database FS also often causes side-effect problems; for example, one
cannot move or copy a SQL Server partition without destroying it.

Of course, that could all change if some corp with deep pockets steps in an
decides to create a "postgresFS" and funds and staffs the effort 100%. But
it's unlikely to be a priority for the existing development team any time in
the forseeable future.

--
Josh Berkus
Aglio Database Solutions
San Francisco