Hi, While running a relaximation test to compare read/write performance between 1.1.x and 1.0.x, I found out that 1.1.x has worst performance
It seems the cause is related to the new Mochiweb version introduced in commit 4b0948ddb3a428f8a5330e05745b2fbd4ccf9375 - https://github.com/apache/couchdb/commit/4b0948ddb3a428f8a5330e05745b2fbd4ccf9375 Comparing the performance of this revision with the previous one (cd214b23e8129868d4a7020ddafd55a16e496652), I get the following results: http://graphs.mikeal.couchone.com/#/graph/df0f79455c9c600f66d1ce42ea0125e5 Both read and write performance are worse for 4b0948ddb3a428f8a5330e05745b2fbd4ccf9375. The cause could be the configuration we pass to Mochiweb in couch_httpd. The new Mochiweb sets the nodelay option to false by default and it uses now several acceptor processes (16 by default). However even with the following small patch I still get about the same disappointing results: diff --git a/src/couchdb/couch_httpd.erl b/src/couchdb/couch_httpd.erl index 23ff7f9..e93c7e7 100644 --- a/src/couchdb/couch_httpd.erl +++ b/src/couchdb/couch_httpd.erl @@ -97,7 +97,9 @@ start_link(Name, Options) -> {ok, Pid} = case mochiweb_http:start(Options ++ [ {loop, Loop}, {name, Name}, - {ip, BindAddress} + {ip, BindAddress}, + {nodelay, true}, + {acceptor_pool_size, 32} ]) of {ok, MochiPid} -> {ok, MochiPid}; {error, Reason} -> (Also tried higher values for acceptor_pool_size, which doesn't help) The test was run like this: $ node tests/compare_write_and_read.js --wclients 100 --rclients 200 \ -name1 new_4b0948ddb3a428f8a5330e05745b2fbd4ccf9375 -name2 old_cd214b23e8129868d4a7020ddafd55a16e496652 \ -url1 http://localhost:5984/ -url2 http://localhost:5985/ \ --duration 120 With the following document template (file relaximation/common/small_doc.json): http://friendpaste.com/7GKUEg0SZHmOf0g7Dh5IWC Can anyone confirm these results? If confirmed, I would say this is a blocker for 1.1.0. thanks -- Filipe David Manana, fdman...@gmail.com, fdman...@apache.org "Reasonable men adapt themselves to the world. Unreasonable men adapt the world to themselves. That's why all progress depends on unreasonable men."
