PECL memcache extension

Paul G paul-lists at perforge.com
Tue Feb 7 00:40:18 UTC 2006


----- Original Message ----- 
From: "Don MacAskill" <don at smugmug.com>
To: "memcached mail list" <memcached at lists.danga.com>
Cc: <mikl at php.net>
Sent: Friday, February 03, 2006 5:37 PM
Subject: PECL memcache extension



-- snip --

> If "set key1" is destined to ServerB's buckets, but ServerB fails, I don't 
> want "key1" being redirected to ServerA instead.  Why?  Because when 
> ServerB comes online, I now have "key1" in two places, and one of them 
> will now potentially get out of date.  Should ServerB fail again before 
> "key1" has expired, calls to "get key1" will return old stale data from 
> ServerA instead of fresh data or no result.
>
> Make sense?  Am I doing something wrong?  Can the PECL extension work in 
> this fashion?

maybe i'm missing something, but i don't think the case you're trying to 
protect against is actually going to occur. once serverB comes back online 
(and gets added to the rotation, which gets rehashed), all further queries 
for key1 will again be run against it, whether it's set or get. sure, you 
get a stale entry for it on serverA, but if it never gets queried for it 
again, who cares?

-p 



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