[Unbound-users] Requestlist size difference 1.3.4 / 1.4.6

[Bagári Péter]

Hi,

I would like to upgrade our unbound servers from 1.3.4 to 1.4.6. We
are currently running the service on dual-core Opteron (2 processors)
linux servers with 16 Gb RAM, peak query rate is 3500 qps per server.
For the live testing with both versions unbound was recompiled with
libev3.9 and python module(not enabled in the config currently). Four
threads are used, outgoing-range and num-queries-per-thread are set to
3072, cache sizes are set to 400/800m.

With the 1.3.4 version during the busy hour the request list contains
120 entries in average, with a variance of 80-180 roughly. In the
early hours it goes down to 20 (10-30). After the change to the new
1.4.6 version, the size of the requestlist has increased, it is at
least 2 times higher, but occasionally it goes up to 500-600
continuously for 1-2 hours, with higher (1500) peaks.
Only the running unbound binary has changed on the test system, apart
from this everything is the same on the server in both cases. Also the
values of the other performance counters stayed on the same level (CPU
usage, recursion times, DNS query counters and so on)

I would like to know the reason of this difference between the two
software versions. I have looked through the release notes, but I
cannot obviously decide whether or not it is only a symptom of one of
the software changes.

Thanks for your help,

Peter