# Multi-threading to the “combine” function

**URL:** <https://discourse.julialang.org/t/multi-threading-to-the-combine-function/67783>\
**Category:** Performance\
**Tags:** multithreading, dataframes, piping\
**Created:** [September 7, 2021, 1:21am UTC](https://discourse.julialang.org/t/multi-threading-to-the-combine-function/67783 "2021-09-07T01:21:14Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![nilshg](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nilshg/32/2283_2.png) [@nilshg](https://discourse.julialang.org/u/nilshg)\
**Post date:** [May 20, 2022, 8:48am UTC](https://discourse.julialang.org/t/multi-threading-to-the-combine-function/67783/3 "2022-05-20T08:48:16Z")

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See

> [@Threading support for DataFrames transforms](https://discourse.julialang.org/t/threading-support-for-dataframes-transforms/79875/2):
>
> If the transformation is thread-safe it would be safe and design is made to ensure this is done the way you want in the future. For GroupedDataFrame we currently use multi-threading already for a sequence of operations. The reason is that usually operations on GroupedDataFrame are more expensive so it was a higher priority to parallelize them. combine under the hood does not differ from transform or select. It is parallelized for GroupedDataFrame but sequential for AbstractDataFrame. Con…

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