You are viewing a plain text version of this content. The canonical link for it is here.
Posted to jira@arrow.apache.org by "Jonathan Keane (Jira)" <ji...@apache.org> on 2021/09/01 17:16:00 UTC

[jira] [Created] (ARROW-13848) [C++] and() in a dataset filter

Jonathan Keane created ARROW-13848:
--------------------------------------

             Summary: [C++] and() in a dataset filter
                 Key: ARROW-13848
                 URL: https://issues.apache.org/jira/browse/ARROW-13848
             Project: Apache Arrow
          Issue Type: Improvement
          Components: C++
            Reporter: Jonathan Keane


Is it expected that a scanning a dataset that has a filter built with {{and()}} is much slower than a filter built with {{and_kleene()}}? Specifically, it seems that {{and()}} triggers a scan of the full dataset, where as {{and_kleene()}} takes advantage of the fact that only one directory of the larger dataset needs to be scanned:

{code:r}
> library(arrow)

Attaching package: ‘arrow’

The following object is masked from ‘package:utils’:

    timestamp

> library(dplyr)
> 
> ds <- open_dataset("~/repos/ab_store/data/taxi_parquet/", partitioning = c("year", "month"))
> 
> system.time({
+ out <- ds %>%
+     filter(arrow_and(total_amount > 100, year == 2015)) %>%
+     select(tip_amount, total_amount, passenger_count) %>%
+     collect()
+ })
   user  system elapsed 
 46.634   4.462   6.457 
> 
> system.time({
+ out <- ds %>%
+     filter(arrow_and_kleene(total_amount > 100, year == 2015)) %>%
+     select(tip_amount, total_amount, passenger_count) %>%
+     collect()
+ })
   user  system elapsed 
  4.633   0.421   0.754 
> 
{code}

I suspect that it's scanning the whole dataset because if I use a dataset that only has the 2015 folder, I get similar speeds:
{code:r}
> ds <- open_dataset("~/repos/ab_store/data/taxi_parquet_2015/", partitioning = c("year", "month"))
> 
> system.time({
+ out <- ds %>%
+     filter(arrow_and(total_amount > 100, year == 2015)) %>%
+     select(tip_amount, total_amount, passenger_count) %>%
+     collect()
+ })
   user  system elapsed 
  4.549   0.404   0.576 
> 
> system.time({
+ out <- ds %>%
+     filter(arrow_and_kleene(total_amount > 100, year == 2015)) %>%
+     select(tip_amount, total_amount, passenger_count) %>%
+     collect()
+ })
   user  system elapsed 
  4.477   0.412   0.585 
{code}



--
This message was sent by Atlassian Jira
(v8.3.4#803005)