#598 DateTime#to_json is slow. - Ruby on Rails

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#598 ✓resolved

DateTime#to_json is slow.

Reported by Alex Zepeda | July 10th, 2008 @ 07:34 PM | in 2.x

The DateTime#to_json method is extremely slow. Converting ~6700 AR objects (with two datetime fields each) to JSON takes roughly 18 seconds on a 2.2GHz Core 2 Duo machine.

This patch simplifies the code, avoiding excessive string operations. End result is about a 5x improvement (~18 to ~2 seconds).

to_json.diff 463 Bytes

Comments and changes to this ticket

You flagged this item as spam.
Alex Zepeda July 10th, 2008 @ 07:34 PM
- Title changed from “Time#to_json” to “Time#to_json is slow.”
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Cheah Chu Yeow July 11th, 2008 @ 03:06 AM
This looks good but it's slightly outdated because it's diffed against the old SVN version of Rails). Don't think Jeremy will have a problem with that though :)
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Ripta Pasay July 12th, 2008 @ 10:25 PM
- Title changed from “Time#to_json is slow.” to “DateTime#to_json is slow.”
- Tag changed from “2.0-stable, activerecord, patch” to “2.0-stable, activesupport, patch”
Benchmarking the changes, I could only get about a 0.25% speed-up at best. I agree the string operation is unnecessary and there was a speed-up, but it seems negligible over a large number of iterations.
```
n = 100,000
              user     system      total        real
original 62.240000   0.090000  62.330000 ( 62.431844)
patched  62.090000   0.090000  62.180000 ( 62.276596)
```
Benchmark attached, in case I missed something.
- date_time_to_json_benchmark.rb 585 Bytes
Repository July 14th, 2008 @ 01:44 AM
(from [9783e66cade4d145389cca18fab822f44d03161a]) Slightly faster DateTime#to_json. [#598 state:resolved] [Alex Zepeda]
http://github.com/rails/rails/co...
Pratik July 14th, 2008 @ 03:03 AM
- State changed from “new” to “resolved”
Repository August 25th, 2008 @ 09:27 AM
(from [50c73c2dfd0d5eb880426e7bc385bcee004ffe3e]) Slightly faster DateTime#to_json. [#598 state:resolved] [Alex Zepeda] http://github.com/rails/rails/co...