[Serusers] Replication problem

Andreas Granig andreas.granig at inode.info
Mon Aug 1 14:24:30 CEST 2005

Greger V. Teigre wrote:
> :-) Jan participated in a discussion on serusers on a new cache system 
> where all locations where not loaded at start-up, but rather at need. 

Well, I just read the thread at
http://lists.iptel.org/pipermail/serusers/2005-May/019867.html and for me 
as a guy who wants to run a scalabe system with a minimum of afford and 
as soon as possible, one question comes up: is it really worth the 
efford to implement such a caching system?

Don't understand me wrong, I'm sure there are a lot of people who 
benefit from this caching mechanism in terms of performance, but my 
experience with this is, well, very bad, when using it in a bigger 

For me (and I think a lot of other people, like Paul, who mentioned it 
too in the above thread) the performance won due to the cache lookup is 
so minimal in combination with my 10-15 other mysql queries and 1-2 enum 
queries per call, that I really don't care, especially when thinking 
about the advantages of a consistend location table in the backend DB:

No need to replicate on SIP level anymore (and there's no really usable 
mechanism for that for more than two SER nodes), no need to distribute 
other contacts like aliases to every single SER node using a remote fifo 
hack, the need of much less memory, much faster startup time and so on, 
and that all for just a few more milliseconds of latency.

So IMHO the option of disabling the cache absolutely makes sense *in 
some circumstances*, like large scale systems.


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