GitHub user dongjoon-hyun opened a pull request:
https://github.com/apache/spark/pull/14583
[SPARK-16994][SQL] PushDownPredicate should not ignore limits.
## What changes were proposed in this pull request?
Currently, `filter` and `limit` are illegally permuted because
`PushDownPredicate` optimizer pushes `filters` through `limit`. This PR fixes
that.
**Reported Error Scenario**
```
scala> spark.createDataset(1 to 100).limit(10).filter($"value" % 10 ===
0).explain
== Physical Plan ==
CollectLimit 10
+- *Filter ((value#875 % 10) = 0)
+- LocalTableScan [value#875]
scala> spark.createDataset(1 to 100).limit(10).filter($"value" % 10 ===
0).collect
res23: Array[Int] = Array(10, 20, 30, 40, 50, 60, 70, 80, 90, 100)
```
**After**
```
scala> spark.createDataset(1 to 100).limit(10).filter($"value" % 10 ===
0).explain
== Physical Plan ==
*Filter ((value#1 % 10) = 0)
+- *GlobalLimit 10
+- Exchange SinglePartition
+- *LocalLimit 10
+- LocalTableScan [value#1]
scala> spark.createDataset(1 to 100).limit(10).filter($"value" % 10 ===
0).collect
res1: Array[Int] = Array(10)
```
## How was this patch tested?
Pass the Jenkins with a new test case.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/dongjoon-hyun/spark SPARK-16994
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/14583.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #14583
----
commit aa84c8e71f8eb636b021ce5f573c8d0694fc19ce
Author: Dongjoon Hyun <[email protected]>
Date: 2016-08-10T16:57:26Z
[SPARK-16994][SQL] PushDownPredicate should not ignore limits.
----
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