Re: O_DIRECT in freebsd

> -----Original Message-----
> From: Jordan Henderson [mailto:jordan_henders(at)yahoo(dot)com]
> Sent: Thursday, October 30, 2003 4:31 PM
> To: sailesh(at)cs(dot)berkeley(dot)edu; Doug McNaught
> Cc: Christopher Kings-Lynne; PostgreSQL-development
> Subject: Re: [HACKERS] O_DIRECT in freebsd
>
> My experience with DB2 showed that properly setup DMS
> tablespaces provided a
> significant performance benefit. I have also seen that the
> average DBA does
> not generally understand the data or access patterns in the
> database. Given
> that, they don't correctly setup table spaces in general,
> filesystem or raw.
> Likewise, where it is possible to tie a tablespace to a
> memory buffer pool,
> the average DBA does not setup it up to a performance
> advantage either.
> However, are we talking about well tuned setups by someone who does
> understand the data and the general access patterns? For a
> DBA like that,
> they should be able to take advantage of these features and
> get significantly
> better results. I would not say it requires considerable
> tuning, but an
> understanding of data, storage and access patterns.
> Additionally, these
> features did not cause our group considerable administrative overhead.

If it is possible for a human with knowledge of this domain to make good
decisions, it ought to be possible to store the same information into an
algorithm that operates off of collected statistics. After some time
has elapsed, and an average access pattern of some sort has been
reached, the available resources could be divided in a fairly efficient
way. It might be nice to be able to tweak it, but I would rather have
the computer make the calculations for me.

Just a thought.