persistent memory management

Hi. I am trying to make my first php extension :) I am sorry, if the question would be too newbiesh, but I just couldn't find a more correct place to ask here is the code: http://loccache.googlecode.com/svn/trunk/loccache.c I am trying to do the following: at the minit-phase I am allocating a persistent HashTable extension has 4 funcitons:

    * loc_set($namespace, $varname, $value); // stores $value
    * loc_get($namespace, $varname) // returns $value from storage
    * loc_isset($namespace, $varname) // returns bool
    * loc_unset($namespace, $varname) // removes varname from storage

during loc_set, I chech if there is "$namespace" item in my persistent hashtable, and if there isn't, I create it as a child hashtable $varname is a key in that second HashTable and $value is the value something like: $big_persistent_hash = array(

     $namespace => array(
         $varname => $value
     )

); extension build and even tends to work... kinda.. unfortunately, persistent values are not too persistent in my case, and i keep getting memory errors. I would be grateful for any help. the source code is not too big :)