At 08:43 a.m. 20/02/2013, Thomas Steinmaurer wrote:

>>
>> As you say, the sum of those 9 page caches will be significant in the 
>> consumption of available RAM.  Additionally, each connection to the SS 
>> process spawns a thread that eats the same amount of RAM as the main process

At 08:43 a.m. 20/02/2013, Thomas Steinmaurer wrote:

>Are we talking about the page cache here only? I'm curious, because this 
>would mean we are close to the CS/SC architecture then. ;-)

No, not closer than it ever was.  SS has one shared cache per open database.  
CS/SC have one cache per connection. The OP has 9 databases per customer.  He 
has n customers (we don't know how many, do we?)  So, in 2GB of RAM, SS will be 
maintaining 9 * n caches of unspecified sizes as well as (potentially) 9 * n * 
m  SS threads (each circa 3.5 MB), where m is the total number of client 
connections.


>> although there's not necessarily a 1:1 correspondence as the server will 
>> reallocate a recently de-allocated thread if one is available.  My point was 
>> that RAM usage will accumulate towards a tipping point on an under-resourced 
>> system like this one.
>
>I fully agree, although I doubt that getting CPU bound is the result of 
>running out of RAM.

50% is CPU-bound?  The main symptom of the OP seemed to be the inability of the 
server to accept new connections.

Actually, it would be interesting to know whether this 32-bit box has SMP.  The 
OP also implied that Oracle and a webserver were hosted on the same box...


Helen Borrie, Support Consultant, IBPhoenix (Pacific)
Author of "The Firebird Book" and "The Firebird Book Second Edition"
http://www.ibphoenix.com/products/books/firebird_book
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