[SPARK-25132][SQL][FOLLOWUP][DOC] Add migration doc for case-insensitive field resolution when reading from Parquet #23238
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…e field resolution when reading from Parquet
|
Test build #99732 has finished for PR 23238 at commit
|
Contributor
Author
|
@HyukjinKwon Would you please kindly take a look at this when you have time? |
docs/sql-migration-guide-upgrade.md
Outdated
|
|
||
| - In Spark version 2.3 and earlier, HAVING without GROUP BY is treated as WHERE. This means, `SELECT 1 FROM range(10) HAVING true` is executed as `SELECT 1 FROM range(10) WHERE true` and returns 10 rows. This violates SQL standard, and has been fixed in Spark 2.4. Since Spark 2.4, HAVING without GROUP BY is treated as a global aggregate, which means `SELECT 1 FROM range(10) HAVING true` will return only one row. To restore the previous behavior, set `spark.sql.legacy.parser.havingWithoutGroupByAsWhere` to `true`. | ||
|
|
||
| - In version 2.3 and earlier, when reading from a Parquet data source table, Spark always returns null for any column whose column names in Hive metastore schema and Parquet schema are in different letter cases, no matter whether `spark.sql.caseSensitive` is set to true or false. Since 2.4, when `spark.sql.caseSensitive` is set to false, Spark does case insensitive column name resolution between Hive metastore schema and Parquet schema, so even column names are in different letter cases, Spark returns corresponding column values. An exception is thrown if there is ambiguity, i.e. more than one Parquet column is matched. This change also applies to Parquet Hive tables when `spark.sql.hive.convertMetastoreParquet` is set to true. |
Member
There was a problem hiding this comment.
Hi, @seancxmao . Maybe, the followings?
- `spark.sql.caseSensitive` is set to true or false
+ `spark.sql.caseSensitive` is set to `true` or `false`
- `spark.sql.caseSensitive` is set to false
+ `spark.sql.caseSensitive` is set to `false`
- `spark.sql.hive.convertMetastoreParquet` is set to true
+ `spark.sql.hive.convertMetastoreParquet` is set to `true`
Contributor
Author
There was a problem hiding this comment.
@dongjoon-hyun Good suggestions. I have fixed them with a new commit.
Member
|
Thank you for adding this to the migration doc. Also, please add |
seancxmao
changed the title
|
Test build #99823 has finished for PR 23238 at commit
|
Member
|
Merged to master and branch-2.4. |
Member
|
Thanks, @seancxmao . |
asfgit
pushed a commit
that referenced
this pull request
Dec 9, 2018
…ive field resolution when reading from Parquet ## What changes were proposed in this pull request? #22148 introduces a behavior change. According to discussion at #22184, this PR updates migration guide when upgrade from Spark 2.3 to 2.4. ## How was this patch tested? N/A Closes #23238 from seancxmao/SPARK-25132-doc-2.4. Authored-by: seancxmao <[email protected]> Signed-off-by: Dongjoon Hyun <[email protected]> (cherry picked from commit 55276d3) Signed-off-by: Dongjoon Hyun <[email protected]>
Contributor
Author
|
Thank you! @dongjoon-hyun |
jackylee-ch
pushed a commit
to jackylee-ch/spark
that referenced
this pull request
Feb 18, 2019
…ive field resolution when reading from Parquet ## What changes were proposed in this pull request? apache#22148 introduces a behavior change. According to discussion at apache#22184, this PR updates migration guide when upgrade from Spark 2.3 to 2.4. ## How was this patch tested? N/A Closes apache#23238 from seancxmao/SPARK-25132-doc-2.4. Authored-by: seancxmao <[email protected]> Signed-off-by: Dongjoon Hyun <[email protected]>
kai-chi
pushed a commit
to kai-chi/spark
that referenced
this pull request
Jul 23, 2019
…ive field resolution when reading from Parquet ## What changes were proposed in this pull request? apache#22148 introduces a behavior change. According to discussion at apache#22184, this PR updates migration guide when upgrade from Spark 2.3 to 2.4. ## How was this patch tested? N/A Closes apache#23238 from seancxmao/SPARK-25132-doc-2.4. Authored-by: seancxmao <[email protected]> Signed-off-by: Dongjoon Hyun <[email protected]> (cherry picked from commit 55276d3) Signed-off-by: Dongjoon Hyun <[email protected]>
kai-chi
pushed a commit
to kai-chi/spark
that referenced
this pull request
Aug 1, 2019
…ive field resolution when reading from Parquet ## What changes were proposed in this pull request? apache#22148 introduces a behavior change. According to discussion at apache#22184, this PR updates migration guide when upgrade from Spark 2.3 to 2.4. ## How was this patch tested? N/A Closes apache#23238 from seancxmao/SPARK-25132-doc-2.4. Authored-by: seancxmao <[email protected]> Signed-off-by: Dongjoon Hyun <[email protected]> (cherry picked from commit 55276d3) Signed-off-by: Dongjoon Hyun <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
What changes were proposed in this pull request?
#22148 introduces a behavior change. According to discussion at #22184, this PR updates migration guide when upgrade from Spark 2.3 to 2.4.
How was this patch tested?
N/A