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https://issues.apache.org/jira/browse/THRIFT-4592?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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James E. King III resolved THRIFT-4592.
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Resolution: Fixed
Assignee: James E. King III
Fix Version/s: 0.12.0
Committed - thanks.
> JS: readI32 performance on large arrays is very poor in Chrome
> --------------------------------------------------------------
>
> Key: THRIFT-4592
> URL: https://issues.apache.org/jira/browse/THRIFT-4592
> Project: Thrift
> Issue Type: Bug
> Components: JavaScript - Library
> Affects Versions: 0.11.0
> Environment: Tested in Chrome 67.0.3396.87 and Safari 11.1.1
> (13605.2.8) on OSX.
> Reporter: Drew Ritter
> Assignee: James E. King III
> Priority: Critical
> Fix For: 0.12.0
>
> Attachments: ThriftBenchmarker.js, readI32_pop.patch
>
>
> `readI32` (
> [https://github.com/apache/thrift/blob/master/lib/js/src/thrift.js#L1311-L1341]
> ) performance is extremely poor in Chrome when reading values from large
> arrays. This is due to the use of Array.shift (
> [https://github.com/apache/thrift/blob/master/lib/js/src/thrift.js#L1322] )
> which seems to have performance issues in V8/Chrome.
>
> As Chrome is a high market share browser I propose either changing this to
> use reverse/pop or detect the appropriate strategy given array length. I
> think this is due to how V8 handles large arrays and the heuristics used to
> determine whether data should be stored in a C-backed array or hash map.
>
> STR:
> 0) Download or copy the attached ThriftBenchmarker.js - this file has some
> helper functions to build large arrays, as well as a copy/paste of the
> current `readI32` as well as one that uses Array.reverse/Array.pop over
> Array.shift.
> 1) Run this test in Chrome - you can simply copy/paste the code into the
> Console.
> 2) Observe that the tests using Array.shift are quite slow in Chrome:
> {code:java}
> -- testing long arrays --
> shift test: 1084.566162109375ms
> pop test: 37.604248046875ms
> -- testing long arrays of strings --
> shift test: 5189.416015625ms
> pop test: 17.9189453125ms
> -- testing short arrays --
> shift test: 0.06005859375ms
> pop test: 0.016845703125ms
> -- testing short arrays of strings --
> shift test: 0.01611328125ms
> pop test: 0.01318359375ms{code}
> 3) Run this test in Safari (or a non-V8) browser.
> 4) Observe that the tests using Array.shift are far faster:
> {code:java}
> -- testing long arrays --
> shift test: 19.235ms
> pop test: 11.774ms
> - testing long arrays of strings --
> shift test: 13.087ms
> pop test: 12.805ms
> - testing short arrays --
> shift test: 0.049ms
> pop test: 0.054ms
> - testing short arrays of strings --
> shift test: 0.039ms
> pop test: 0.022ms{code}
> [^ThriftBenchmarker.js]
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