On 04/19/12 08:28, Attila Nagy wrote:
So getting an exact document took .098921 seconds (nearly 98.9 milliseconds) on a completely idle machine.Any subsequent queries are in the order of the above response time, which is just slow.Is this what CouchDB and Erlang capable of, or something is wrong in my setup? I haven't turned compression off, BTW, but will measure its effect.
Without compression: 07:43:03.822390 HTTP GET /test/1 07:43:03.823475 HTTP/1.1 200 OK 07:43:03.919761 the JSON data so the response time is .097371 seconds (97.37 ms)In the mean time, I've found that somewhere in time CouchDB/HTTPd turned TCP NODELAY to off, so
socket_options = [{nodelay, true}]
gives: 2.47 ms response time, which is a major increase.
I could lower that down to 2.1 ms by switching to
null_authentication_handler, which is not good, but better.
On query performance: when I fetch the same documents (one by one, ID number one to the last) from three different machines on four threads on each of them (so 12 concurrent HTTP GETs can be on the wire), I can saturate one CPU core (Xeon X5670 @ 2.93GHz, I've limited it to one core) to 100% CouchDB and can get about 1700 query/sec performance.
These are just plain HTTP GETs, so no JSON parsing is involved.Switching to persistent connections gives 2200 query/sec (again, CouchDB maxes the CPU out).
I hope some day CouchDB will be able to deliver performance too.
