so memcached provides a lot of stats to track usage (hits and misses).
sample output -
stats STAT pid 1 STAT uptime 982226 STAT time 1630949306 STAT version 1.6.6 STAT libevent 2.0.21-stable STAT pointer_size 64 STAT rusage_user 18.366158 STAT rusage_system 19.678998 STAT max_connections 65000 STAT curr_connections 7 STAT total_connections 3953 STAT connection_structures 17 STAT response_obj_bytes 2480 STAT response_obj_total 2 STAT response_obj_free 1 STAT response_obj_oom 0 STAT read_buf_bytes 32768 STAT read_buf_bytes_free 16384 STAT read_buf_oom 0 STAT reserved_fds 10 STAT cmd_get 8 STAT cmd_set 3980 STAT cmd_flush 0 STAT cmd_touch 0 STAT cmd_config_get 65475 STAT cmd_config_set 1 STAT cmd_meta 0 STAT get_hits 0 STAT get_misses 8 STAT get_expired 0 STAT get_flushed 0 STAT delete_misses 0 STAT delete_hits 0 STAT incr_misses 0 STAT incr_hits 0 STAT decr_misses 0 STAT decr_hits 0 STAT cas_misses 0 STAT cas_hits 0 STAT cas_badval 0 STAT touch_hits 0 STAT touch_misses 0 STAT auth_cmds 0 STAT auth_errors 0 STAT bytes_read 4273871 STAT bytes_written 94622147 STAT limit_maxbytes 13932429312 STAT launch_time_maxbytes 13932429312 STAT accepting_conns 1 STAT listen_disabled_num 0 STAT time_in_listen_disabled_us 0 STAT threads 2 STAT conn_yields 0 STAT hash_power_level 16 STAT hash_bytes 524288 STAT hash_is_expanding 0 STAT curr_config 1 STAT malloc_fails 0 STAT log_worker_dropped 0 STAT log_worker_written 0 STAT log_watcher_skipped 0 STAT log_watcher_sent 0 STAT bytes 9202 STAT curr_items 50 STAT total_items 3939 STAT slab_global_page_pool 0 STAT expired_unfetched 3889 STAT evicted_unfetched 0 STAT evictions 0 STAT reclaimed 3889 STAT crawler_reclaimed 0 STAT crawler_items_checked 0 STAT lrutail_reflocked 0 stats around get, delete, incr, delete are present in this list. However, my application has extensive use of add and that does not have any specific metric to show for itself when it fails to update.
How can I check how many were actually added and how many were not added?
Note that I can do this from the app - by logging, etc. but am looking for a way to get this from the monitoring metrics for memcached.
Is this even possible?
STAT cmd_set 3980