Hello Klaus,
On 03/04/2009 03:01 PM, Klaus Darilion wrote:
Hi!
Sorry for not knowing how hash table works, thus my questions may be a bit stupid:
How many items can be stored in hashtable? Is it limited to "size" parameter, e.g. 10 means max. 1024 entries? Or is it as much as memory is available (what for is the size parameter in this case)?
As much memory you have. The hash table is an array of lists. The array has the size (number of entries) 2 power "size".
For each item is computed an integer hash value and the item is stored in hash_array[hash_value%array_size].
The higher size decreases the chances of hash value collisions, so when searching, you jump directly to the list holding the item and that lists is not very big.
Most of modules that stores something in memory uses this approach (e.g., usrloc).
How can I delete a key from htable? Example: I want to track concurrent calls (lets pretend there is no dialog module :-):
# pseudo language if INVITE $sht(a=>$ci) = $ts; ...
elseif BYE $avp(s:duration) = $ts - $avp(s:duration);
# how to delete this key now from the htable?
$sht(a=>$ci) = null;
Is it possible to iterate over all entries in the htable?
No, there are some operations that can work on many items based on regexp for deletion:
http://kamailio.org/docs/modules/1.5.x/htable.html#id2467797
Cheers, Daniel