7 Čen
2013
7 Čen
'13
15:28
On 07/06/2013 15:12, Marek Vavruša wrote:
Hi Marek,
Thanks for your explanation. I do understand that the virtual memory
usage will of course be higher than actual memory usage. I also notice
that not all memory is instantly freed when zones are removed. For
example, when I load an unsigned zone with about 3.9 million records, it
makes knot use 1.3 GB of RAM. If I then remove the zone from the config
file and reload knot, the RAM usage only drops down to 1.1 GB. if I then
add the zone back, and reload knot, the memory usage climbs as knot
loads the zone. It hits 2.1 GB, and then when the zone is fully loaded,
the memory drops to 1.9 GB. So now there appears to be another 600 MB of
RAM in usage, probably held in unfreed resources. I don't know whether
knot should immediately release memory, or whether it does lazy
cleanups, so this may be a feature or a bug :)
Coming back to doing estimates: yes a tool that makes an estimate based
on the zone file would be great. I asked for something similar for NSD4,
and Wouter has written such a tool. It's very useful for getting some
idea of how much extra memory I will need per zone, and what NSD's final
usage will be (of course it will use some more in practice, but that's
understood).
Regards,
Anand
Hi Anand,
the estimate highly depends on the zone contents of course,
the estimate seems like a good upper bound.
I remember measuring about 500MB (signed) zone and it yielded about 1.3G as
well,
but the virtual memory was at about 2G due to how memory allocation works.
So it's not entirely clear what essentialy IS used memory and what is just
waste or kept.
The best course of action would be to write a tool that is able to make
better estimate
based on the zone file, would that be okay?