How to find the keys being evicted from memcache?

Question

Is there any inbuilt way/ or a hack by which I can know which key is being evicted from memcache ?

There is one solution of polling for all possible keys inserted into memcache (e.g. get multi), but that is inefficient and certainly not implementable for large number of keys.

The functionality is not needed to be run in production, but during some benchmarking and optimization runs.

What are you going to do with these keys and how quickly do you need them? — mikewied, Apr 08 '14 at 08:20
@mikewied just need them to monitor the patterns of eviction.Not really realtime,a minor delay of few seconds is acceptable. — DhruvPathak, Apr 08 '14 at 09:58
Can you just log then and then parse the log file? That would probably be the easiest thing to do if it's an option. — mikewied, Apr 08 '14 at 22:14
@mikewied That seems good, but how do I log the keys being evicted from memcache ? — DhruvPathak, Apr 09 '14 at 05:54

score 2 · Accepted Answer · answered Apr 16 '14 at 08:43

Not possible AFAIK, but a really good (and simple) solution is to modify your memcached library and do a print (or whatever you want) in the delete and multidelete methods. You can then get the keys that are being deleted (both by your app and by the library itself). I hope that helps

How to find the keys being evicted from memcache?

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