Re: [ADMIN] request for tuning suggestions from PC Week Labs

On Sun, Jan 30, 2000 at 12:56:39AM -0500, Timothy Dyck wrote:
> Hi all, I'm the database analyst for PC Week Labs and am comparing
> PostgreSQL with Inprise's InterBase (which will be open sourced later this
> year). As part of this project, I'm running a benchmark with a mix of OLTP
> and DSS queries in a set of various mixes and at a variety of user loads
> (up to 100 concurrent users). I'd like to get your tuning suggestions on
> the engine to make sure I am not missing anything.
>
> My test server is a departmental-type machine with two Pentium III 450MHz
> CPUs with 512MB of RAM running RedHat Linux 6.1. PGDATA is pointing to a
> RAID 5 array and the database is ~40 MB of data before indexing, and so
> will fit entirely into the db cache. The OS swapfile is not used at all. I
> will be using ODBC to query the database.
>
> 1. The biggest performance item I've seen in looking through the mailing
> lists is the fsync option. I want to leave this enabled as I don't think a
> transactional database should ever lose data. My understanding is that
> with it on PG checkpoints after every commit. Is there a way to let the
> log grow to a certain size before checkpointing? When fsync is off, how is
> data loss possible?
>
> 2. How do I move the log to a different spindle from the disks the
> database data is on?
>
> 3. Any other suggestions are much appreciated.

The speed of fsync is a filesystem issue.

Reiserfs is generally somewhat faster than ext2, and has journaling.
Unfortenately I think the log can only be used for metadata right now -
but you shold check that with the developers.



--
Ragnar Kjørstad