hi, i think it the same bug with issue#370, and i have found the reproduce way and pull a fix patch to github.
在 2014年7月2日星期三UTC+8上午5时43分49秒，Dormando写道： > > Hey, > > Can you presize the hash table? (-o hashpower=nn) to be large enough on > those servers such that hash expansion won't happen at runtime? You can > see what hashpower is on a long running server via stats to know what to > set the value to. > > If that helps, we might still have a bug in hash expansion. I see someone > finally reproduced a possible issue there under .20. .17/.19 fix other > causes of the problem pretty thoroughly though. > > On Tue, 1 Jul 2014, Denis Samoylov wrote: > > > Hi, > > We had sporadic memory corruption due tail repair in pre .20 version. So > we updated some our servers to .20. This Monday we observed several > > crushes in .15 version and tons of "allocation failure" in .20 version. > This is expected as .20 just disables "tail repair" but it seems the > > problem is still there. What is interesting: > > 1) there is no visible change in traffic and only one slab is affected > usually. > > 2) this always happens with several but not all servers :) > > > > Is there any way to catch this and help with debug? I have all slab and > item stats for the time around incident for .15 and .20 version. .15 is > > clearly memory corruption: gdb shows that hash function returned 0 (line > 115 uint32_t hv = hash(ITEM_key(search), search->nkey, 0);). > > > > so we seems hitting this comment: > > /* Old rare bug could cause a refcount leak. We haven't seen > > * it in years, but we leave this code in to prevent > failures > > * just in case */ > > > > :) > > > > Thank you, > > Denis > > > > -- > > > > --- > > You received this message because you are subscribed to the Google > Groups "memcached" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected] <javascript:>. > > For more options, visit https://groups.google.com/d/optout. > > > > -- --- You received this message because you are subscribed to the Google Groups "memcached" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
