curr_items never decreases
woodbri at swoodbridge.com
Thu May 18 14:09:46 UTC 2006
Brian Moon wrote:
> Just Marc wrote:
>> I'm using memcached 1.1.12 from Debian unstable, and it seems that
>> even though items do expire (verified by seeing that they are no
>> longer available after the timeout via mc_get), curr_items doesn't
>> decrease, ever.
> To make memcached a fast beast, it does lazy clean up (not sure of the
> proper term). That means, things are not removed just because they
> expire. They stay in the cache. If asked for however, and they are
> expired, they are not returned. This makes for a much simpler, and
> faster cache system.
> IMO, the key metrics to watch when deciding if the cache is effective is
> the hits and misses. We have a hit/miss ratio of about 900:1. After a
> while, you learn not to worry about the number of items, size, etc. As
> long as you have a good hit/miss ratio things are working well for you.
> And, before you wonder, no, there is no current way to get a count of
> unexpired items from the cache.
What is the best way to get hit/miss stats? Are these stored in the
server and retrievable through the stats interface? We use the Perl API.
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