SERVER_ERROR out of memory on small puts to memcache.

dormando dormando at rydia.net
Mon Nov 12 02:06:40 UTC 2007


*pulls old mail out of garbage*

Curious if you're still having this issue? If it's been fixed/etc? I 
didn't see any noise on the list about it since.

Matt Knox wrote:
> I consistently get an out of memory error when performing  < 44 byte 
> (key+data) puts to memcache, but when 'put'-ing the same key with data 
> that is long enough to exceed 44 chars key + data  , I succeed.  I 
> observe this behavior using both the ruby client (memcache-client 1.5) 
> and the python one (python-memcached), although the python client seems 
> to break at 59 chars, rather than 44.

Spiffy! Can't reproduce it on a 64-bit host. Haven't tried 32-bit.

> I'm running memcached 1.2.2 with the following options:
> 
> memcached -d -p 11211 -u nobody -c 1024 -m 3072
> 
> The offending servers are recent CentOS running 3G of cache each on 
> 32-bit boxes with 4G ram-if it matters, I can get details about these.

I suspect that's a big deal. The maxbytes limit doesn't include random 
buffers that are used for connections, stats commands, this and that. So 
you'll be apt to bowl over the 32-bit address space. I've never trusted 
that the different splits even work.

So, if you are still having this issue:

- How'd you build memcached?
- Exactly what version of centos?
- Does it happen after memcached has been up for a long time, or 
immediately?
- Does it still happen if you lower the -m option to 1.6-1.8 gigabytes?

Thanks,
-Dormando


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