GitHub user rxin opened a pull request:
https://github.com/apache/spark/pull/17839
[SPARK-20576][SQL] Support generic hint function in Dataset/DataFrame
## What changes were proposed in this pull request?
We allow users to specify hints (currently only "broadcast" is supported)
in SQL and DataFrame. However, while SQL has a standard hint format (/*+ ...
*/), DataFrame doesn't have one and sometimes users are confused that they
can't find how to apply a broadcast hint. This ticket adds a generic hint
function on DataFrame that allows using the same hint on DataFrames as well as
SQL.
As an example, after this patch, the following will apply a broadcast hint
on a DataFrame using the new hint function:
```
df1.join(df2.hint("broadcast"))
```
## How was this patch tested?
Added a test case in DataFrameJoinSuite.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/rxin/spark SPARK-20576
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/17839.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 #17839
----
commit 921eb21d0bbb65715617a019ce13b53e2c868121
Author: Reynold Xin <r...@databricks.com>
Date: 2017-05-03T06:02:51Z
[SPARK-20576][SQL] Support generic hint function in Dataset/DataFrame
----
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
