GitHub user robertkowalski opened a pull request:
https://github.com/apache/couchdb-couch/pull/56
perf: http layer - cache couchdb version
I have taken a look at our http stack with erlang:trace and flamegraphs.
It turned out that we spend a lot of our time for ever request in the
function couch_server:get_version which simply gets the current CouchDB
version. [1]
So I tried to memoize it, with pretty good results [2].
I benchmarked the unclustered interface, but (almost?) all our
requests are accessing this function so it should also be beneficial
for chttpd & friends.
After a better looking flamegraph i tried to run Apache ab
[[3]](http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/results-ab.txt)
on it.
All benchmarks (also the flamegraph creation) were run using this test
protocol:
1. turn off all auto starting apps, especially dropbox & co
2. run make with path
3. reboot
4. wait 60secs
5. boot cluster and wait until successful connected
6. wait 60secs
7. run test
Apache âabâ:
10000 requests, concurrency 130, reading one doc, unclustered
interface:
old version, overall run times:
test 1: 3.846
test 2: 3.830
patched version, overall run times:
test 1: 3.439
test 2: 3.577
mean difference:
(3.846 + 3.830) / (3.439 + 3.577) * 100
patched version is ~9.4% faster
The implementation of the cache itself is a simple orddict that is
meant for caching a small amount of these time consuming operations.
[1]
http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/flame--unpatched-second-request.png
[2]
http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/flame--patched-second-request.png
[3]
http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/results-ab.txt
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/robertkowalski/couchdb-couch increase-perf
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/couchdb-couch/pull/56.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #56
----
commit 4f205dc0f6210ce342ea65994c1eef46674ee8f0
Author: Robert Kowalski <[email protected]>
Date: 2015-05-29T13:25:00Z
perf: http layer - cache couchdb version
I have taken a look at our http stack with erlang:trace and flamegraphs.
It turned out that we spend a lot of our time for ever request in the
function couch_server:get_version which simply gets the current CouchDB
version. [1]
So I tried to memoize it, with pretty good results [2]. I benchmarked
the unclustered interface, but (almost?) all our requests are accessing
this function so it should also be beneficial for chttpd & friends.
After a better looking flamegraph i tried to run Apache ab [3] on it.
All benchmarks (also the flamegraph creation) were run using this test
protocol:
1. turn off all auto starting apps, especially dropbox & co
2. run make with path
3. reboot
4. wait 60secs
5. boot cluster and wait until successful connected
6. wait 60secs
7. run test
Apache âabâ:
10000 requests, concurrency 130, reading one doc, unclustered
interface:
old version, overall run times:
test 1: 3.846
test 2: 3.830
patched version, overall run times:
test 1: 3.439
test 2: 3.577
mean difference:
(3.846 + 3.830) / (3.439 + 3.577) * 100
patched version is ~9.4% faster
The implementation of the cache itself is a simple orddict that is
meant for caching a small amount of these time consuming operations.
[1]
http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/flame--unpatched-second-request.png
[2]
http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/flame--patched-second-request.png
[3]
http://robert-kowalski.de/assets/data/2015-05-29-erlang-perf/results-ab.txt
----
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