On Nov 3, 2008, at 1:34, Jan Lehnardt wrote:
Another part is the Erlang to JSON conversion that is known to be
slow-ish. I don't know which side of the conversion weighs more
though. We are working with the Erlang community and developers to
get a C-based JSON encoder into Erlang. Since building a view server
is relatively straightforward, giving a Perl version a shot is
probably worth it.
You are right that it's the Erlang side that's slow. beam.smp uses
~100% CPU while couchjs just uses 10-15% (depending on the complexity
of the map function).
Even just inserting documents (a few KB each) is going sloowly.
Inserting 2000 new documents is taking about 12 seconds on 2.5GHz of
whatever Intel's new server CPUs are called.
Is that right? I'm using SVN as of a few days ago.
(RAID 10 on 14 15k SAS disks, many more GB ram than the dataset etc -
as far as I can tell the workload is entirely CPU bound - there are 8
CPU cores, but as I understand it CouchDB basically only uses more
than one when updating views, and even then it's limited by the main
process being CPU bound).
Which Erlang version are you running. R11B-x is known for causing
view-build slowness.
R12B-3 and R12B-4 are good.
I think I'm using R12B-3. The RPM I am using is erlang-R12B-3.3.el5.
- ask
