Aaron Abend wrote:

>
> My question was intended to see if there were some known issues that would
> prevent FB from using more memory, which might therefore put more pressure
> on the CPU (I know this can happen with SQL Server and Oracle).
>

Not particularly, though Firebird does tend to use less memory than some
other databases. Typically, however, the very high CPU usage is related
to index garbage collection - indexes with lots of duplicates and lots
of back versions of records. You said your application was single user,
but some single user applications make multiple connections and a
background connection that starts a snapshot transaction and never
closes it can cause old index entries to build up.

>
>
> I have increased the DefaultDbCachePages to 5120 pages and we use 16k pages
> –so it should be able to go up to 80M on this machine (which is running xp
> with 512M ram). But all it uses is 20M. why won’t it use more? Is some other
> parameter limiting memory use? Or is memory simply not the problem and it
> just needs a ton of CPU to process the queries?

The page cache is allocated as pages are read - there's no pre-loading.
The symptom of too little cache is heavy I/O load, not CPU.


Regards,


Ann