couchdb-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Konstantin Cherkasoff <>
Subject Re: High latency (40ms) and low request rate (10 rps) under windows
Date Wed, 26 Oct 2011 23:32:13 GMT

> What happens when you set delayed_commits to true?
With delayed_commits I got about 150 rps so delayed_commits mode is 15
times faster.

> With that off you are requiring an fsync (iirc)  after every value written and then
are at the
> mercy at your disks write performance (but not in the sense of burst-write
> as these are individual, disparate write requests coming in).

Yes, I understand that many small writes and fsyncs can be a
bottleneck in this case.
But I found that the increase of number of concurrent requests lead to
an increase in the request rate.
For example (100 concurent requests)
> ab -k -t 10 -c 100 -n 1000000 -p ab.json -T "application/json" http://localhost:5984/bench
shows about 300 RPS (writes and fsyncs) on the same hardware.

So, I suppose that 10 requests per second actually is not the limit
for this hard disk.
And there may be some other problem.

> Also, is this build Couch Single Server from Couchbase or some other Windows build of
I tried Couchbase 1.2.0 and
this build


View raw message