You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@spark.apache.org by "Jacob Eisinger (JIRA)" <ji...@apache.org> on 2016/10/03 15:38:20 UTC
[jira] [Comment Edited] (SPARK-17728) UDFs are run too many times
[ https://issues.apache.org/jira/browse/SPARK-17728?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15542689#comment-15542689 ]
Jacob Eisinger edited comment on SPARK-17728 at 10/3/16 3:37 PM:
-----------------------------------------------------------------
Thanks for the explanation and the tricky code snippet! I kind of figured it was optimizing incorrectly / over optimizing. It sounds like this is not a defect because normally this optimization of collapsing projects is the desired route. Correct?
Do you think it is worth filing a feature request to allow working with costly UDFs? Possibly:
* Memoize UDFs / other transforms on a per row basis.
* Manually override costs for UDFs.
was (Author: jeisinge):
Thanks for the explanation and the tricky code snippet! I kind of figured it was optimizing incorrectly / over optimizing. It sounds like this is not a defect because normally this optimization of collapsing projects is the desired route. Correct?
Do you think it is worth filing a feature request to allow working with costly UDFs? Possibly:
* Memoize UDFs / other transforms on a per row basis.
* Manually override costs for UDFs.
> UDFs are run too many times
> ---------------------------
>
> Key: SPARK-17728
> URL: https://issues.apache.org/jira/browse/SPARK-17728
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 2.0.0
> Environment: Databricks Cloud / Spark 2.0.0
> Reporter: Jacob Eisinger
> Priority: Minor
> Attachments: over_optimized_udf.html
>
>
> h3. Background
> Llonger running processes that might run analytics or contact external services from UDFs. The response might not just be a field, but instead a structure of information. When attempting to break out this information, it is critical that query is optimized correctly.
> h3. Steps to Reproduce
> # Create some sample data.
> # Create a UDF that returns a multiple attributes.
> # Run UDF over some data.
> # Create new columns from the multiple attributes.
> # Observe run time.
> h3. Actual Results
> The UDF is executed *multiple times* _per row._
> h3. Expected Results
> The UDF should only be executed *once* _per row._
> h3. Workaround
> Cache the Dataset after UDF execution.
> h3. Details
> For code and more details, see [^over_optimized_udf.html]
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org