[horde] IMP IMAP DB Cache backend lifetime

[Joao S Veiga]

----- Message from Jens Wahnes <wahnes at uni-koeln.de> ---------
> Joao S Veiga wrote:
>> Even with very few users, without Frederico's suggestion the cache  
>> in the database will grow forever if not manually cleared (and the  
>> imp-query-imap-cache doesn't help much for old messages/metadata).
>>
>> So for the sql cache to properly work in any case, there should be  
>> a way to expire them, as he suggested.
>
> I agree that Horde should be able to clean up the mess it created.  
> ;-) But then, OTOH, the Horde configuration already comes with a big  
> "NOT RECOMMENDED" message regarding usage of a SQL database for  
> caching, so go figure.
>

Where? In my imp/backends.php it says 'sql' is one of the recommended  
caching system, for better performance:

  *     - 'cache': Caching is enabled using the Horde cache (configured in
  *                horde/config/conf.php). It is recommended to use either
  *                'hashtable', 'nosql', or 'sql' instead, as these backends
  *                have better performance.
  *                The 'cache_lifetime' parameter (integer) can be specified
  *                to define the lifetime of the cached message data.
  *     - 'hashtable': Caching is enabled using the Horde HashTable driver
  *                    (configured in horde/config/conf.php).
  *                    The 'cache_lifetime' parameter (integer) can be
  *                    specified to define the lifetime of the cached message
  *                    data.
  *     - 'nosql': Caching is enabled using the Horde NoSQL database
  *                (configured in horde/config/conf.php).
  *     - 'sql': Caching is enabled using the Horde SQL database (configured in
  *              horde/config/conf.php).

Is it marked as "NOT RECOMMENDED" somewhere else? I'm using it due to  
this text in the backends.php.

Joao