Adding a NIF based JSON decoding/encoding module
------------------------------------------------
Key: COUCHDB-1118
URL: https://issues.apache.org/jira/browse/COUCHDB-1118
Project: CouchDB
Issue Type: Improvement
Components: Database Core
Reporter: Filipe Manana
Fix For: 1.2
Currently, all the Erlang based JSON encoders and decoders are very slow, and
decoding and encoding JSON is something that we do basically everywhere.
Via IRC, it recently discussed about adding a JSON NIF encoder/decoder. Damien
also started a thread at the development mailing list about adding NIFs to
trunk.
The patch/branch at [1] adds such a JSON encoder/decoder. It is based on Paul
Davis' eep0018 project [2]. Damien made some modifications [3] to it mostly to
add support for big numbers (Paul's eep0018 limits the precision to 32/64 bits)
and a few optimizations. I made a few corrections and minor enhancements on top
of Damien's fork as well [4]. Finally Benoît identified some missing
capabilities compared to mochijson2 (on encoding, allow atoms as strings and
strings as object properties).
Also, the version added in the patch at [1] uses mochijson2 when the C NIF is
not loaded. Autotools configuration was adapted to compile the NIF only when
we're using an OTP release >= R13B04 (R13B03 NIF API is too limited and
suffered many changes compared to R13B04 and R14) - therefore it should work on
any OTP release > R13B at least.
I successfully tested this on R13B03, R13B04 and R14B02 in an Ubuntu
environment.
I'm not sure if it builds at all on Windows - would appreciate if someone could
verify it.
Also, I'm far from being good with the autotools, so I probably missed
something important or I'm doing something in a not very standard way.
This NIF encoder/decoder is about one order of magnitude faster compared to
mochijson2 and other Erlang-only solutions such as jsx. A read and writes test
with relaximation shows this has a very positive impact, specially on reads
(the EJSON encoding is more expensive than JSON decoding) -
http://graphs.mikeal.couchone.com/#/graph/698bf36b6c64dbd19aa2bef634052381
@Paul, since this is based on your eep0018 effort, do you think any other
missing files should be added (README, etap tests, etc)? Also, should we put
somewhere a note this is based on your project?
[1] - https://github.com/fdmanana/couchdb/compare/json_nif
[2] - https://github.com/davisp/eep0018
[3] - https://github.com/Damienkatz/eep0018/commits/master
[4] - https://github.com/fdmanana/eep0018/commits/final_damien
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
