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Posted to jira@arrow.apache.org by "Dominik Moritz (Jira)" <ji...@apache.org> on 2021/04/25 18:39:00 UTC
[jira] [Commented] (ARROW-10220) [JS] Cache javascript utf-8
dictionary keys?
[ https://issues.apache.org/jira/browse/ARROW-10220?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17331610#comment-17331610 ]
Dominik Moritz commented on ARROW-10220:
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I like the idea of caching the strings and I'm happy to help with TypeScript. You can join the #arrow-js channel on the-asf.slack.com.
> [JS] Cache javascript utf-8 dictionary keys?
> --------------------------------------------
>
> Key: ARROW-10220
> URL: https://issues.apache.org/jira/browse/ARROW-10220
> Project: Apache Arrow
> Issue Type: Improvement
> Components: JavaScript
> Affects Versions: 1.0.1
> Reporter: Ben Schmidt
> Priority: Minor
> Labels: pull-request-available
> Time Spent: 40m
> Remaining Estimate: 0h
>
> String decoding from arrow tables is a major bottleneck in using arrow in Javascript–it can take a second to decode a million rows. For utf-8 types, I'm not sure what could be done; but some memoization would help utf-8 dictionary types.
> Currently, the javascript implementation decodes a utf-8 string every time you request an item from a dictionary with utf-8 data. If arrow cached the decoded strings to a native js Map, routine operations like looping over all the entries in a text column might be on the order of 10x faster. Here's an observable notebook [benchmarking that and a couple other strategies|https://observablehq.com/@bmschmidt/faster-arrow-dictionary-unpacking].
> I would file a pull request, but 1) I would have to learn some typescript to do so, and 2) this idea may be undesirable because it creates new objects that will increase the memory footprint of a table, rather than just using the typed arrays.
> Some discussion of how the real-world issues here affect the arquero project is [here|https://github.com/uwdata/arquero/issues/1].
>
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