On Mon, Jul 25, 2011 at 8:45 AM, Andrej van der Zee < [email protected]> wrote:
> >> *) What is the number of items on your server and the memory they consume? >> Could it be that you're not storing the items in the first place? >> > > I guess you mean those stats: > > Personally I prefer _all_ stats, not just a subset ;) > STAT curr_items 86535 > These are the current number of objects in the system.. all of them may in theory be expired, but we're evaluating that lazily so we don't know yet.. > STAT total_items 134552 > These are the total count of object you've had in the system since startup... Out of the 134k of object you've put in there, 48k is no longer there.. If you sample this a few times, does it keep on growing? > STAT bytes 27267454 > > What does that tell me? > > Actually, I am not sure if memcached is used for caching MySQL or Tomcat > session-related stuff. Is there any way to get to the content of the cached > objects so I can find out without bothering anybody? I think I have > read-acces as I am able to get results with "echo stats | nc 127.0.0.1 > 11211". > You can't get the content without knowing the key (it's not exactly true, but close ;-)) > > > >> *) Are you sure the client is using the same hashing method to locate the >> server during store and fetch? Could it be that you're trying to fetch from >> another server than you're storing the object to? >> > > Could be, I don't know. > > >> *) If you're having a lot of items there, what's the eviction rate of the >> server?? Could it be that you're simply "trashing"? >> > > STAT evictions 0 > > What does that tell me? > That you're not forcibly kicking out objects from the cache to replace with new objects (unless there is a bug in the version you're having that doesn't update the counter).. > > > >> *) If you're not having evictions, do you use timeouts on your objects? >> Could it be that your objects time out before you try to access them again? >> > > No clue. How can I find out without bothering anybody? > > What about just grabbing a few network packets to look at the traffic you're sending to your memcached server and look from there? It would be a lot easier for you to figure out if you knew what they used the memcached cluster for ;) It could be that they don't store and fetch the same kinds of objects ;) -- Trond Norbye
