"The size of the lock table is governed more by the number of buffers in
use than any other single issue. Firebird holds one lock per user
accessing a buffer, plus one lock per table referenced per user, plus
locks on transactions, and a bunch of miscellaneous locks. However, the
interesting ones are buffer locks since they tend to be numerous and
volatile."

Would it be difficult to implement lock manager defaults that vary based
on the number of buffers? When we deploy FB 2.0 I plan on having a one
gigabyte page buffer for a database, and the previous post implies that
I'll have to increase the lock buffers appropriately.

-----Original Message-----
From: firebird-support@yahoogroups.com
[mailto:firebird-support@yahoogroups.com] On Behalf Of Ann W. Harrison
Sent: Friday, September 22, 2006 12:32 PM
To: firebird-support@yahoogroups.com
Subject: Re: [firebird-support] Fatal lock manager error: invalid lock
id (3527612) errorno:0

Hi Dalton,

>
> I am running with a standard configuration, and the time period
> between such problems is averaging a month so a debug version on this
> database system, would not be practical.

Unfortunately, that's probably the only way to find the bug unless
someone has a brilliant insight. I think it's possible to run a server
compiled for debug and setup to produce a core file when it hits that
error without having a debugger involved in the actual running. But we
can return to that later.

>
> So, perhaps it is an issue with lock parametres. What setting would
> you recommend for a database that has about 150 concurrent connections

> at any one time with a average database size of 30 GB? The number of
> tables, procedures and views is also on the order of about a thousand
> objects or more......

The size of the lock table is governed more by the number of buffers in
use than any other single issue. Firebird holds one lock per user
accessing a buffer, plus one lock per table referenced per user, plus
locks on transactions, and a bunch of miscellaneous locks. However, the
interesting ones are buffer locks since they tend to be numerous and
volatile.

If you have not changed the lock parameters from the installation, try
changing these parameters:

#
#LockMemSize = 262144

Uncomment it and set it to 1Mb (1048576)

#LockHashSlots = 101

Uncomment it and set it to 401

Changing the parameters won't find or fix the bug - the change just
hides the bug until systems get bigger and faster and we trip over it
again. And if the bug is not a boundary condition on lock table size,
changing the parameters won't help at all.
But it shouldn't hurt.

Best,


Ann


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