id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc
328,pdns-recursor performance heavily degrades after 2GB (?) usage.,dgamble,ahu,"We have noticed on two of our recently-upgraded 3.3 pdns-recursor machines that the service's performance takes a massive hit after running for a few days.  Some forensics reveals that this occurs as soon as the recursor is using 2GB of memory.

CPU usage is at expected levels for a day or so after the machine is restarted.  The machine's performance graphs show that 2GB memory usage is the ""magic point"" at which the problem occurs.  Then, CPU usage of the pdns-recursor process will then increase to about 5x its previous value.  Restarting the process will temporarily alleviate the issue.

We have worked around this issue by only having one thread spawn, which halves memory usage.  Halving max-cache-entries with keeping two threads also seems to prevent this, although performance is not nearly as good.  However both workarounds limit the capacity of the recursor.

We have seen this appear on the 3.3 recursor.  We can not confirm or not if this is present on 3.2 as the upgrades were done from 3.1.",defect,new,normal,,recursor,3.3,major,,,