Memcached stats reset command

Stats reset is another undocumented feature (see this article for stats cachedump command) of Memcached

stats reset command

Telnet command : stats reset \r\n

This function will reset following stats :

• total_connections
• get, set, flush, cas, incr and decr stats
• auth_cmds and auth_errors
• bytes_read and bytes_written
• total_items will be reset but not curr_items
• evictions and reclaimed

stats reset command example

First we get the current stats :

stats

stats
STAT pid 16963
STAT uptime 13759537
STAT time 1288017338
STAT version 1.4.5
STAT pointer_size 64
STAT rusage_user 35326.604539
STAT rusage_system 83474.312975
STAT curr_connections 443
STAT total_connections 7062593
STAT connection_structures 708
STAT cmd_get 6994013410
STAT cmd_set 285664007
STAT cmd_flush 11
STAT get_hits 6709348930
STAT get_misses 284664480
STAT delete_misses 133333
STAT delete_hits 641874
STAT incr_misses 0
[...]
STAT auth_errors 0
STAT bytes_read 1078950472291
STAT bytes_written 2380539854758
STAT limit_maxbytes 1610612736
[...]
STAT conn_yields 0
STAT bytes 1019869479
STAT curr_items 1019724
STAT total_items 285630709
STAT evictions 187149
STAT reclaimed 4867645
END

Now we reset Memcached server stats

stats reset
RESET

The final result :

stats

STAT pid 16963
STAT uptime 13759736
STAT time 1288017537
STAT version 1.4.5
STAT pointer_size 64
STAT rusage_user 35327.040473
STAT rusage_system 83475.259831
STAT curr_connections 456
STAT total_connections 2
STAT connection_structures 708
STAT cmd_get 2117
STAT cmd_set 101
STAT cmd_flush 0
STAT get_hits 2018
STAT get_misses 99
STAT delete_misses 0
STAT delete_hits 0
STAT incr_misses 0
[...]
STAT auth_errors 0
STAT bytes_read 154416
STAT bytes_written 689536
STAT limit_maxbytes 1610612736
[...]
STAT conn_yields 0
STAT bytes 1019306738
STAT curr_items 1019534
STAT total_items 101
STAT evictions 0
STAT reclaimed 0

Be aware that using this function can hide you a lot of things, i find it only useful when we put a new version of cache management to reset all stats and start monitoring the new version without the stats history.

Other Memcached Resources

You can find a lot of Memcached resources on this Memcached resources page.