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Posted to jira@arrow.apache.org by "Andrew Lamb (Jira)" <ji...@apache.org> on 2020/12/21 18:25:00 UTC
[jira] [Updated] (ARROW-11002) [Rust] Improve speed of JSON nested
list reader
[ https://issues.apache.org/jira/browse/ARROW-11002?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Andrew Lamb updated ARROW-11002:
--------------------------------
Description:
The code that reads in nested lists in rust/arrow/src/json/reader.rs does an extra copy (via `Vec::clone`) that caused 20% slowdown in a benchmark compared to not cloning.
The goal of this ticket would be to improve the performance of reading JSON in this case, likely by avoiding the clone
More details can be found here:
https://github.com/apache/arrow/pull/8938#pullrequestreview-556273641
As [~nevi_me] says:
{quote}
I suspect the main perf loss is from having to peek into JSON values in order to make the nesting work.
By this, I mean that if we have {"a": [_, _, _]}, we extract a values into a Vec<Value>, i.e. [_, _, _].
By extracting values, we are able to then use the reader to read &[Value] without caring about its key (a).
The downside of this approach is that we have to clone values to get Vec<Value>, as I couldn't find an alternative
{quote}
was:
The code that reads in nested lists in rust/arrow/src/json/reader.rs does an extra copy (via `Vec::clone`) that caused 20% slowdown in a benchmark compared to not cloning.
The goal of this ticket would be to improve the performance of reading JSON in this case, likely by avoiding the clone
More details can be found here:
https://github.com/apache/arrow/pull/8938#pullrequestreview-556273641
As [~nevi_me] says:
> I suspect the main perf loss is from having to peek into JSON values in order to make the nesting work.
> By this, I mean that if we have {"a": [_, _, _]}, we extract a values into a Vec<Value>, i.e. [_, _, _].
> By extracting values, we are able to then use the reader to read &[Value] without caring about its key (a).
> The downside of this approach is that we have to clone values to get Vec<Value>, as I couldn't find an alternative
> [Rust] Improve speed of JSON nested list reader
> -----------------------------------------------
>
> Key: ARROW-11002
> URL: https://issues.apache.org/jira/browse/ARROW-11002
> Project: Apache Arrow
> Issue Type: Improvement
> Components: Rust
> Reporter: Andrew Lamb
> Priority: Minor
>
> The code that reads in nested lists in rust/arrow/src/json/reader.rs does an extra copy (via `Vec::clone`) that caused 20% slowdown in a benchmark compared to not cloning.
> The goal of this ticket would be to improve the performance of reading JSON in this case, likely by avoiding the clone
> More details can be found here:
> https://github.com/apache/arrow/pull/8938#pullrequestreview-556273641
> As [~nevi_me] says:
> {quote}
> I suspect the main perf loss is from having to peek into JSON values in order to make the nesting work.
> By this, I mean that if we have {"a": [_, _, _]}, we extract a values into a Vec<Value>, i.e. [_, _, _].
> By extracting values, we are able to then use the reader to read &[Value] without caring about its key (a).
> The downside of this approach is that we have to clone values to get Vec<Value>, as I couldn't find an alternative
> {quote}
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