memcached (1.2.5) stuck in infinite loop

Miguel DeAvila miguel.j.deavila at
Thu Apr 10 04:40:00 UTC 2008

On Wednesday 09 April 2008 17:16:49 you wrote:
> We were discussing this problem yesterday in IRC and its probably
> something that will be looked at the hackathon next week.
> Do you have a test case for this by any chance? I don't :(

No ... no test case, though just putting the servers into
production does the trick.   ;-)

We're getting the hangs pretty regularly, so we can probably
provide some additional instrumentation if that helps.

> This problem seems to occur in both single and multi thread build and I'm
> suspecting that the problem could be in the table expansion logic
> though I can't say for sure (well, tracing h_next assignments kinda makes
> you suspect it).
> I've modified one of our memcached servers to allocate enough buckets
> relative to the number of records that we wont exceed so that the expansion
> logic wont be triggered (just to see if it'll hang after a week or so
> of operation).

What about the opposite test ... forcing a server to do the expansion more
frequently then normal ... perhaps that will provoke the error?
Let me know what I can do to help.



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