SERVER_ERROR out of memory on small puts to memcache.

[Jeremy Blain]

I've seen this happen in the past as well, but forgot about it till now.
Bouncing the server also fixed it.

My not very thorough looking about seemed to suggest the cache had
allocated all it's slabs already to certain sized objects, and it wanted
to store the current object in a slab that had chunks of sizes that
didn't exist.




Matt Knox wrote:

> The problem seems to have gone away on bouncing memcache, and we can't
> replicate it, even though we started memcache in exactly the same way,
> on the same machines.  We'll probably make 3 1Gb instances instead of
> the 3G instances if it recurs. 
>
> thanks for the help!
>
> matt
>
>
> On Nov 11, 2007 9:06 PM, dormando <dormando at rydia.net
> <mailto:dormando at rydia.net>> wrote:
>
>     *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
>
>
>