memcached何时删除项目？

Question

I'm relatively new to memcached and only know the basics of getting it set up and working. I've run into an issue on our Magento-based website where the cache is growing too large and causing some slowness when editing product details. I telnetted to the memcached server and ran stats and noticed that there were nearly 900 megs and over 65500 items in there. I typed the flush_all command and re-ran stats and it's still the same. After some research I have found that flushing it invalidates the entries but doesn't actually free up the space. It will do so over time as new items are added. From what I have seen, it never frees up the nearly 900 megs of space and never deletes the 65000+ items that seem to be stuck in there. I haven't tried restarting memcached yet as this is a live site and I don't want to cause any problems. If restarting the server frees up the space, that's still not a solution because I don't want to have to do that every time. Can someone please help me understand what's going on and how I can fix this?

Answer 1

You'll want to tweak the maximum amount of memory Memcached is allowed to use in an instance. At the command line, the -m flag is used to set the maximum number of megabytes the cache can hold. Flushing the cache merely invalidates everything in it, and the items are evicted lazily. If you want memcached to use less memory, there's no getting around it: you'll have to restart it with less memory.