[Tickets #10072] Re: Memcache storage is duplicating the key prefix

bugs at horde.org bugs at horde.org
Mon May 16 21:39:12 UTC 2011


Ticket URL: http://bugs.horde.org/ticket/10072
  Ticket             | 10072
  Updated By         | Michael Slusarz <slusarz at horde.org>
  Summary            | Memcache storage is duplicating the key prefix
  Queue              | Horde Framework Packages
  Version            | Git master
  Type               | Bug
  State              | Unconfirmed
  Priority           | 1. Low
  Milestone          |
  Patch              | 1
  Owners             |

Michael Slusarz <slusarz at horde.org> (2011-05-16 21:39) wrote:

>> I still don't understand why this is an issue.  Please don't tell me
>> you are looking at key names in your memcache (or any) backend.
>> Because that is completely irrelevant.
> Yes, i was debugging memcache get() and set() methods.
>> All that matters is that for a given key input to Cache::get() (or
>> Cache::set()), a single, unique data value is associated with it.  If
>> a key has 2, 3 (or 10) prefixes tacked on to the front, why does that
>> matter?
> I think it matters, because without the patch after a single login i  
> have (ex) 30 keys being created on cache. With the patch i only have  
> like 12 or 13.. this is because without the patch every key is  
> created twice in the database (one with one prefix the other with  
> the prefix 2 times) and some are even created 3 times...
> I don't say that memcache is not working correctly, im just saying  
> that i think there's some problem with it. The way i see it having  
> in the memcache something like:
> PREFIX_number_of_session
> PREFIX_PREFIX_number_of_session

If this is happening then this *might* be an error.  You will have to  
track down where these alleged duplicate prefixes are being generated  
(Horde::debug() might be useful for this).

Note that just because the data value is the same, that does NOT mean  
that the key is being duplicated.  That is a dangerous assumption and  
is simply wrong.

FWIW, your patch doesn't fix this problem at all.  All you are doing  
is removing the prefix feature, which is not the correct solution.

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