Hello,
On 6/29/12 11:07 PM, Vitaliy Aleksandrov wrote:
Hi all,
I use $sht() pseudo-variabled provided by htable module for caching
various information about sip customers. I thought that htable has
some locking mechanism inside it and today while i was reading
core-cookbook i payed attention to one example with the lock/unlock
functions and $sht():
lock("calls-to::10.10.10.10");
$sht(a=>calls-to::10.10.10.10) =
$sht(a=>calls-to::10.10.10.10) + 1;
unlock("calls-to::10.10.10.10");
According to that example an explicit locking mechanism should be used
when i want to write something to a hash table.
On the other hand there are no locks in htable documentation.
So the question is when do the explicit locks should be used and for
what purpose ?
reading and writing in hash table is under the lock. But the increment
operation as it is presented above requires first to read and then to
write -- for that is recommended you use a lock to avoid races.
If it is just increment/decrement operation in htable, then you can use
$shtinc(...)/$shtdec(...) for it:
http://www.kamailio.org/wiki/cookbooks/3.3.x/pseudovariables#shtinc_htable_key
Cheers,
Daniel
--
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio Advanced Training, Seattle, USA, Sep 23-26, 2012 -
http://asipto.com/u/katu
Kamailio Practical Workshop, Netherlands, Sep 10-12, 2012 -
http://asipto.com/u/kpw
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