[jira] [Updated] (ARROW-16578) [R] unique() and is.na() on a column of a tibble is much slower after writing to and reading from a parquet file

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-16578?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ASF GitHub Bot updated ARROW-16578:
-----------------------------------
    Labels: pull-request-available  (was: )

> [R] unique() and is.na() on a column of a tibble is much slower after writing to and reading from a parquet file
> ----------------------------------------------------------------------------------------------------------------
>
>                 Key: ARROW-16578
>                 URL: https://issues.apache.org/jira/browse/ARROW-16578
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: Parquet, R
>    Affects Versions: 7.0.0, 8.0.0
>            Reporter: Hideaki Hayashi
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> unique() on a column of a tibble is much slower after writing to and reading from a parquet file.
> Here is a reprex.
> {{df1 <- tibble::tibble(x=as.character(floor(runif(1000000) * 20)))}}
> {{write_parquet(df1,"/tmp/test.parquet")}}
> {{df2 <- read_parquet("/tmp/test.parquet")}}
> {{system.time(unique(df1$x))}}
> {{# Result on my late 2020 macbook pro with M1 processor:}}
> {{#   user  system elapsed }}
> {{#  0.020   0.000   0.021 }}
> {{system.time(unique(df2$x))}}
> {{#   user  system elapsed }}
> {{#  5.230   0.419   5.649 }}
>  
>  



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