Hi

Aage Johansen wrote:

>On Tue, 10 Feb 2004 06:30:07 +0000 (UTC), Venus Software Operations wrote:
>
> > I have just recently tried a few samples with FireBird and now will be
> > going for a small app.
> > Could you tell me what kind of maintenance/tuning will I be required for
> > a FireBird database?
>
>
>Hardly any tuning is required, and there isn't much to tune.
>Choose a page size that suits your data (size of database) - 4KB or 8KB is
>fine for most situations.
>Choose a buffer size (depending on architecture: CS or SS), number of
>active databases, and available RAM (and for CS: active users).
>With SS, start at 5000-10000 pages for cache size if this fits with RAM
>size etc. I don't know whether the old 'truth' that one should not exceed
>about 10.000 cache pages (which makes for about 80MB RAM with 8KB page
>size) for a database still holds.
>Use gbak regularly, and occasionally do a restore to a new database to
>check that backups are OK.
>That's it.
>Make sure that transaction numbers advance properly (no stuck or
>everlasting transactions) - if you have a period of inactivity (no users
>connected) you might schedule a SWEEP to clean up transaction numbers and
>garbage.
>Check that you don't have indexes with very bad selectivity on large
>tables. ("bad' selecticity means 'low' selectivity which in IB/Fb is
>indicated by a high number - IIRC).
>I don't us CS, so ...
>
>
>

How low is a low selectivity should be? Is there a computation?

Thanks

James