memcached Item Statistics
To get the items statistics, use the stats items command, or the API equivalent.
The items statistics give information about the individual items allocated within a given slab class.
STAT items:2:number 1 STAT items:2:age 452 STAT items:2:evicted 0 STAT items:2:evicted_nonzero 0 STAT items:2:evicted_time 2 STAT items:2:outofmemory 0 STAT items:2:tailrepairs 0 ... STAT items:27:number 1 STAT items:27:age 452 STAT items:27:evicted 0 STAT items:27:evicted_nonzero 0 STAT items:27:evicted_time 2 STAT items:27:outofmemory 0 STAT items:27:tailrepairs 0
The prefix number against each statistics relates to the corresponding chunk size, as returned by the stats slabs statistics. The result is a display of the number of items stored within each chunk within each slab size, and specific statistics about their age, eviction counts, and out of memory counts. A summary of the statistics is given in the following table.
| Statistic | Description | |
|---|---|---|
number
| The number of items currently stored in this slab class. | |
age
| The age of the oldest item within the slab class, in seconds. | |
evicted
| The number of items evicted to make way for new entries. | |
evicted_time
| The time of the last evicted entry | |
evicted_nonzero
| The time of the last evicted non-zero entry | 1.4.0 |
outofmemory
| The number of items for this slab class that have triggered an out of memory error (only value when the -M command line option is in effect).
| |
tailrepairs
| Number of times the entries for a particular ID need repairing |
Item level statistics can be used to determine how many items are stored within a given slab and their freshness and recycle rate. You can use this to help identify whether there are certain slab classes that are triggering a much larger number of evictions that others.