Need help understanding memcached stats

Scott Newman snewman18 at
Tue Feb 13 05:32:53 UTC 2007

> Especially since it looks like 5378 of those misses later led to writes,
> given the cmd_set being 5378. So, I'd guess that in no case has your
> cache ever had a cache miss after writing the data into the cache. This
> seems totally unsurprising, since it looks like the size of your cache
> (limit_maxbytes) is 256 meg, and the data you're storing in your cache
> is only taking up 12735133 bytes, or 12 megs (or so -- I'm not good at
> base 2 math in my head :)).
> So, unless I'm reading something wrong, it looks like you can cache
> 10-20 times as much stuff as you currently are, and still not fill up
> the cache.

Thanks, this information is extremely helpful to me. Here are a couple
follow-up questions - I hope they are not dumb, I want to make sure
I'm not working with false assumptions about what I'm reading:

1. It seems like a miss should result in a write, and indeed the
numbers are very close. When would a miss not result in a write?

2. What do current connections/total connections represent? (how is a
connection defined - is it anything like a web server session?)

3. Similarly, what do current items/total items represent? I'm
guessing that current items are items in cache that are not expired?
Are total items minus current items the number of items in cache that
are expired?


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