David Vogelbacher created SPARK-28761:
-----------------------------------------
Summary: spark.driver.maxResultSize only applies to compressed data
Key: SPARK-28761
URL: https://issues.apache.org/jira/browse/SPARK-28761
Project: Spark
Issue Type: Improvement
Components: Spark Core
Affects Versions: 3.0.0
Reporter: David Vogelbacher
Spark has a setting `spark.driver.maxResultSize`, see
https://spark.apache.org/docs/latest/configuration.html#application-properties :
{noformat}
Limit of total size of serialized results of all partitions for each Spark
action (e.g. collect) in bytes. Should be at least 1M, or 0 for unlimited. Jobs
will be aborted if the total size is above this limit. Having a high limit may
cause out-of-memory errors in driver (depends on spark.driver.memory and memory
overhead of objects in JVM). Setting a proper limit can protect the driver from
out-of-memory errors.
{noformat}
This setting can be very useful in constraining the memory that the spark
driver needs for a specific spark action. However, this limit is checked before
decompressing data in
https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/scheduler/TaskSetManager.scala#L662
Even if the compressed data is below the limit the uncompressed data can still
be far above. In order to protect the driver we should also impose a limit on
the uncompressed data. We could do this in
https://github.com/apache/spark/blob/master/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala#L344
I propose adding a new config option {{spark.driver.maxUncompressedResultSize}}.
A simple repro of this with spark shell:
{noformat}
> printf 'a%.0s' {1..100000} > test.csv # create a 100 MB file
> ./bin/spark-shell --conf "spark.driver.maxResultSize=10000"
scala> val df = spark.read.format("csv").load("/Users/dvogelbacher/test.csv")
df: org.apache.spark.sql.DataFrame = [_c0: string]
scala> val results = df.collect()
results: Array[org.apache.spark.sql.Row] =
Array([aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...
scala> results(0).getString(0).size
res0: Int = 100000
{noformat}
Even though we set maxResultSize to 10 MB, we collect a result that is 100MB
uncompressed.
--
This message was sent by Atlassian JIRA
(v7.6.14#76016)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
