Deletes Are Driving Me Crazy

[Matthew Glubb]

Okay, I guess I can expand a little :)

You are right to guess that I am using memcache as a queue of sorts.  
It's network related.

Each client has a maximum of N key/value pairs in the memcache.  
Multiple, concurrent requests may be arriving from the same client.  
Every client uses the same key prefix for all of there keys ie.  
prefix_[0 to N-1]. If a client tries to overwrite one of those key/ 
value pairs once they have been assigned the request is denied, hence  
the requirement for using add rather than set. If a client session  
ends, all N key/value pairs should be deleted. If the same client  
then starts another session they should be able to recreate up to N  
key/value pairs using the same key names but containing different  
values.

I have multiple red hat boxes running lighttpd and load-balanced fast- 
cgi php 5.0.5 modules with John's mcache extension 1.2.0 beta10  
compiled against libmemcache-1.4.0.b9. Memcached is version 1.1.12.

Sometimes it works, sometimes it doesn't. It seems to me that deleted  
keys are not always deleted 'straightaway'.

Matt

On 11 Jan 2006, at 17:24, Jeff Rodenburg wrote:

> On 1/11/06, Matthew Glubb <matt at zgroupplc.com> wrote:
>>
>> I simply wish to be able to delete a key that has a zero expiry
>> period and then immediately be able to add a key of the same name.
>> The reason that I cannot use set is because if it already exists in
>> the cache I do not want to replace the value.
>>
>
> I have a somewhat similar requirement, but I'm curious about this  
> specific
> approach.  It sounds as if an object may go into the cache with a  
> given key,
> but in some scenarios if that key is already in use, that object  
> would use a
> different key in the cache.  Is that accurate?
>
> This sound as if you might be using the cache as a queue or  
> something to
> delineate prioritization or ordering.
>
> I know this doesn't resolve the particular add/delete/add scenario,  
> but I'm
> curious about the requirements side.
>
> cheers,
> j



m a t t h e w   g l u b b

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