robreeves opened a new pull request, #40812:
URL: https://github.com/apache/spark/pull/40812
<!--
Thanks for sending a pull request! Here are some tips for you:
1. If this is your first time, please read our contributor guidelines:
https://spark.apache.org/contributing.html
2. Ensure you have added or run the appropriate tests for your PR:
https://spark.apache.org/developer-tools.html
3. If the PR is unfinished, add '[WIP]' in your PR title, e.g.,
'[WIP][SPARK-XXXX] Your PR title ...'.
4. Be sure to keep the PR description updated to reflect all changes.
5. Please write your PR title to summarize what this PR proposes.
6. If possible, provide a concise example to reproduce the issue for a
faster review.
7. If you want to add a new configuration, please read the guideline first
for naming configurations in
'core/src/main/scala/org/apache/spark/internal/config/ConfigEntry.scala'.
8. If you want to add or modify an error type or message, please read the
guideline first in
'core/src/main/resources/error/README.md'.
-->
### What changes were proposed in this pull request?
<!--
Please clarify what changes you are proposing. The purpose of this section
is to outline the changes and how this PR fixes the issue.
If possible, please consider writing useful notes for better and faster
reviews in your PR. See the examples below.
1. If you refactor some codes with changing classes, showing the class
hierarchy will help reviewers.
2. If you fix some SQL features, you can provide some references of other
DBMSes.
3. If there is design documentation, please add the link.
4. If there is a discussion in the mailing list, please add the link.
-->
This modifies the `InMemoryRelation.clone` method to clone the cached plan.
### Why are the changes needed?
When caching is used the cached part of the SparkPlan is leaked to new
clones of the plan.
### Does this PR introduce _any_ user-facing change?
Yes. It fixes a driver hanging issue the user can observe.
### How was this patch tested?
Unit test added and I manually verified cloned plans don't reference the
original plan objects with this script.
```scala
import org.apache.spark.sql.execution.SparkPlan
import org.apache.spark.sql.execution.columnar.InMemoryTableScanExec
import spark.implicits._
def findCacheOperator(plan: SparkPlan): Option[InMemoryTableScanExec] = {
if (plan.isInstanceOf[InMemoryTableScanExec]) {
Some(plan.asInstanceOf[InMemoryTableScanExec])
} else if (plan.children.isEmpty && plan.subqueries.isEmpty) {
None
} else {
(plan.subqueries.flatMap(p => findCacheOperator(p)) ++
plan.children.flatMap(findCacheOperator)).headOption
}
}
val df = spark.range(10).filter($"id" < 100).cache()
val df1 = df.limit(1)
val df2 = df.limit(1)
// Get the cache operator (InMemoryTableScanExec) in each plan
val plan1 = findCacheOperator(df1.queryExecution.executedPlan).get
val plan2 = findCacheOperator(df2.queryExecution.executedPlan).get
// Check if InMemoryTableScanExec references point to the same object
println(plan1.eq(plan2))
// returns false
// Check if InMemoryRelation references point to the same object
println(plan1.relation.eq(plan2.relation))
// returns false
// Check if the cached SparkPlan references point to the same object
println(plan1.relation.cachedPlan.eq(plan2.relation.cachedPlan))
// returns false
// This shows that the bug is fixed. Without the fix this returned true.
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
