Stats Output, Counters vs. Gauge.

timeless time at
Tue Jan 24 09:39:13 UTC 2006

I'm trying to graph the output of memcache::getExtendedStats() in 
RRDtool (Cacti, actually), but can't quite figure out which stats are 
counters (always increasing) vs. gauges (a measure of the current value, 
may rise or fall).

I had assumed that curr_items, total_connections, and total_items would 
be gauges, but it looks like at least curr_items is a counter, or items 
aren't flushed from the cache (I put things in the cache with an expiry 
of 30 seconds in all cases).

Here's a screenshot:

Notice that the Current Items statistic is increasing about linearly 
(the graph is logarithmic, so it looks like it's levelling off, but it 
isn't). The two places where the graph drops is where I restarted 
memcached. I do not expect this. Does anyone have a definitive list of 
which items are counters and which are gauges?

Once I get the stats correct, I'll put the Cacti host template online 
for people to graph their MemcacheD statistics, alongside the MySQL 
Cacti host template here:


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