ARROW-15622: [R] Implement union_all and union for arrow_dplyr_query

[wjones127]

This PR adds support for dplyr::union and dplyr::union_all. Not sure why, but I find I must use the fully qualified name dplyr::union or else will get an error.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-15622

[wjones127]

Some example usage:

library(arrow)
#> 
#> Attaching package: 'arrow'
#> The following object is masked from 'package:utils':
#> 
#>     timestamp
library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union

tab1 <- arrow_table(x = 1:3)
tab2 <- arrow_table(x = 2:4, y = c("a", "b", "c"))

tab1 |>
    mutate(y = "a") |>
    union_all(tab2) |>
    collect()
#> # A tibble: 6 × 2
#>       x y    
#>   <int> <chr>
#> 1     2 a    
#> 2     3 b    
#> 3     4 c    
#> 4     1 a    
#> 5     2 a    
#> 6     3 a

tab1 |>
    mutate(y = "a") |>
    union_all(tab2) |>
    arrange(x, y) |>
    collect()
#> # A tibble: 6 × 2
#>       x y    
#>   <int> <chr>
#> 1     1 a    
#> 2     2 a    
#> 3     2 a    
#> 4     3 a    
#> 5     3 b    
#> 6     4 c

tab1 |>
    mutate(y = "a") |>
    dplyr::union(tab2) |>
    arrange(x, y) |>
    collect()
#> # A tibble: 5 × 2
#>       x y    
#>   <int> <chr>
#> 1     1 a    
#> 2     2 a    
#> 3     3 a    
#> 4     3 b    
#> 5     4 c

^{Created on 2022-05-09 by the reprex package (v2.0.1)}

[wjones127]

The timeouts on RTools mingw seem to be random. I ran locally on mingw64 and was able to get it to build and pass all R tests.

[nealrichardson]

Not sure why, but I find I must use the fully qualified name dplyr::union or else will get an error.

Probably namespace collision:

> union
function (x, y) 
{
    u <- as.vector(x)
    v <- as.vector(y)
    unique(c(u, v))
}
<bytecode: 0x1290ae500>
<environment: namespace:base>

[nealrichardson]

A couple of suggestions on the tests but otherwise LGTM, thanks!

[ursabot]

Benchmark runs are scheduled for baseline = 6576aa0 and contender = d889ade. d889ade is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Failed ⬇️0.7% ⬆️0.0%] test-mac-arm
[Failed ⬇️0.37% ⬆️0.0%] ursa-i9-9960x
[Finished ⬇️0.47% ⬆️0.04%] ursa-thinkcentre-m75q
Buildkite builds:
[Finished] d889adec ec2-t3-xlarge-us-east-2
[Failed] d889adec test-mac-arm
[Failed] d889adec ursa-i9-9960x
[Finished] d889adec ursa-thinkcentre-m75q
[Finished] 6576aa06 ec2-t3-xlarge-us-east-2
[Failed] 6576aa06 test-mac-arm
[Failed] 6576aa06 ursa-i9-9960x
[Finished] 6576aa06 ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java

[ursabot]

['Python', 'R'] benchmarks have high level of regressions.
test-mac-arm