Ever had the nagging sense that all that caching work you’ve just done, isn’t yielding the results you had hope for? Or perhaps you don’t seem to be getting the improvement you once did, or you see evidence in your logs that things are being cached, then further down, there’s data being generated prematurely?
How do you go about find out what is going on?
Well, you can start by reading the memcached text protocol, and then use what you’ve learned there to interrogate memcached using telnet or netcat or any tool you prefer. We’re going to use netcat, its pretty ubiquitous and simple for this purpose. We’re also going to assume you’re on the same box as the memcached instances that you’re interested in, and that its running on port 11211.
$echo stats|nc localhost 11211
STAT pid 29232
STAT uptime 13096670
STAT version 1.4.5
STAT cmd_get 16082428
STAT cmd_set 385658032
STAT cmd_flush 21
STAT get_hits 926923674
STAT get_misses 479158754
STAT bytes_read 13877916015974
STAT bytes_written 3063162027584
STAT limit_maxbytes 3460300800
STAT bytes 2787768823
STAT curr_items 57949
STAT total_items 385657951
STAT evictions 367643811
STAT reclaimed 14770696
END
$
