oplock problem

Johann Zuschlag
Thu, 08 Jul 1999 11:45:36 -0000

On Thu, 8 Jul 1999 09:01:31 +1000, David Collier-Brown wrote:

>	have you tries with oplocks turned off?  That's the "normal"
way
>	one runs database-like PC apps.

That seems logical for me since caching is switched off if several clients
access one, e.g. database, file. The funny thing is that since a database client
software
update we got oplock breaks. Switching oplocks off fixed the problem. I guess
the WIN95/98 clients aren't behaving well. And finally, if one machine
crashes you
lose the cached data leaving you with an inconsistant database.

The real question is: What are the best settings for multiuser database
applications concerning speed (index searching). I tried different things like
changes in the
socket options, didn't change anything. After I updated to fast ethernet the
database access speed didn't really change. The database (45Mbyte) seems to
fit in the
memory of Linux (2.0.35 with Samba 1.9.18.p8, 198Mbyte RAM). No disk access is
needed (and seen) but still index searching is pretty slow, while single dataset
access is good.

Copying large files from the server is really fast (3.5 Mbyte/s no switch, just
a hub!). So server and network speed should be ok. Maybe there is no reason to
have
read prediction=on since the clients just look for small datasets. So Samba
shouldn't read too large chunks. Or are there other changes to be done?
Maybe a client
with a Celeron 300A is just to slow. :-) Or TCP/IP is limiting that?

Just to make my point clear: If a single user accesses the database with
oplocks=true, index search is really fast. But that is not the scenario I'm
looking for.

Any ideas?

Thanks in advance,

- Johann


Johann Zuschlag
jozuschlag@online.de