### What changes were proposed in this pull request?
Update migration guide according to https://github.com/apache/spark/pull/30942#issuecomment-755054562
### Why are the changes needed?
update migration guide.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Not need
Closes#31051 from AngersZhuuuu/SPARK-32685-FOLLOW-UP.
Authored-by: angerszhu <angers.zhu@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
For same SQL
```
SELECT TRANSFORM(a, b, c, null)
ROW FORMAT DELIMITED
USING 'cat'
ROW FORMAT DELIMITED
FIELDS TERMINATED BY '&'
FROM (select 1 as a, 2 as b, 3 as c) t
```
In hive:
```
hive> SELECT TRANSFORM(a, b, c, null)
> ROW FORMAT DELIMITED
> USING 'cat'
> ROW FORMAT DELIMITED
> FIELDS TERMINATED BY '&'
> FROM (select 1 as a, 2 as b, 3 as c) t;
OK
123\N NULL
Time taken: 14.519 seconds, Fetched: 1 row(s)
hive> packet_write_wait: Connection to 10.191.58.100 port 32200: Broken pipe
```
In Spark
```
Spark master: local[*], Application Id: local-1609225830376
spark-sql> SELECT TRANSFORM(a, b, c, null)
> ROW FORMAT DELIMITED
> USING 'cat'
> ROW FORMAT DELIMITED
> FIELDS TERMINATED BY '&'
> FROM (select 1 as a, 2 as b, 3 as c) t;
1 2 3 null NULL
Time taken: 4.297 seconds, Fetched 1 row(s)
spark-sql>
```
We should keep same. Change default ROW FORMAT FIELD DELIMIT to `\u0001`
In hive default value is '1' to char is '\u0001'
```
bucket_count -1
column.name.delimiter ,
columns
columns.comments
columns.types
file.inputformat org.apache.hadoop.hive.ql.io.NullRowsInputFormat
```
### Why are the changes needed?
Keep same behavior with hive
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Added UT
Closes#30958 from AngersZhuuuu/SPARK-33930.
Authored-by: angerszhu <angers.zhu@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
Update the SQL migration guide about the changes made by:
- https://github.com/apache/spark/pull/30778
- https://github.com/apache/spark/pull/30711
- https://github.com/apache/spark/pull/30866
### Why are the changes needed?
To inform users about the recent changes in the upcoming releases.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
N/A
Closes#30925 from MaxGekk/sql-migr-guide-hiveclientimpl.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
Addressed comments in PR #30567, including:
1. add test case for SPARK-33647 and SPARK-33142
2. add migration guide
3. add `getRawTempView` and `getRawGlobalTempView` to return the raw view info (i.e. TemporaryViewRelation)
4. other minor code clean
### Why are the changes needed?
Code clean and more test cases
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Existing and newly added test cases
Closes#30666 from linhongliu-db/SPARK-33142-followup.
Lead-authored-by: Linhong Liu <linhong.liu@databricks.com>
Co-authored-by: Linhong Liu <67896261+linhongliu-db@users.noreply.github.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This PR intends to escape meta-characters (e.g., \n and \t) in `Dataset.showString`.
Before this PR:
```
scala> Seq("aaa\nbbb\t\tccccc").toDF("value").show()
+--------------+
| value|
+--------------+
|aaa
bbb ccccc|
+--------------+
```
After this PR:
```
+-----------------+
| value|
+-----------------+
|aaa\nbbb\t\tccccc|
+-----------------+
```
### Why are the changes needed?
For better output.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Added a unit test.
Closes#30647 from maropu/EscapeMetaInShow.
Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
Add migration guide for CHAR VARCHAR types
### Why are the changes needed?
for migration
### Does this PR introduce _any_ user-facing change?
doc change
### How was this patch tested?
passing ci
Closes#30654 from yaooqinn/SPARK-33641-F.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This PR aims to enable `spark.sql.adaptive.enabled` by default for Apache Spark **3.2.0**.
### Why are the changes needed?
By switching the default for Apache Spark 3.2, the whole community can focus more on the stabilizing this feature in the various situation more seriously.
### Does this PR introduce _any_ user-facing change?
Yes, but this is an improvement and it's supposed to have no bugs.
### How was this patch tested?
Pass the CIs.
Closes#30628 from dongjoon-hyun/SPARK-33679.
Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
This PR intends to fix typos in the sub-modules:
* `bin`
* `core`
* `docs`
* `external`
* `mllib`
* `repl`
* `pom.xml`
Split per srowen https://github.com/apache/spark/pull/30323#issuecomment-728981618
NOTE: The misspellings have been reported at 706a726f87 (commitcomment-44064356)
### Why are the changes needed?
Misspelled words make it harder to read / understand content.
### Does this PR introduce _any_ user-facing change?
There are various fixes to documentation, etc...
### How was this patch tested?
No testing was performed
Closes#30530 from jsoref/spelling-bin-core-docs-external-mllib-repl.
Authored-by: Josh Soref <jsoref@users.noreply.github.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
### What changes were proposed in this pull request?
This PR makes CreateViewCommand/AlterViewAsCommand capturing runtime SQL configs and store them as view properties. These configs will be applied during the parsing and analysis phases of the view resolution. Users can set `spark.sql.legacy.useCurrentConfigsForView` to `true` to restore the behavior before.
### Why are the changes needed?
This PR is a sub-task of [SPARK-33138](https://issues.apache.org/jira/browse/SPARK-33138) that proposes to unify temp view and permanent view behaviors. This PR makes permanent views mimicking the temp view behavior that "fixes" view semantic by directly storing resolved LogicalPlan. For example, if a user uses spark 2.4 to create a view that contains null values from division-by-zero expressions, she may not want that other users' queries which reference her view throw exceptions when running on spark 3.x with ansi mode on.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
added UT + existing UTs (improved)
Closes#30289 from luluorta/SPARK-33141.
Authored-by: luluorta <luluorta@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
In [SPARK-33139] we defined `setActionSession` and `clearActiveSession` as deprecated API, it turns out it is widely used, and after discussion, even if without this PR, it should work with unify view feature, it might only be a risk if user really abuse using these two API. So revert the PR is needed.
[SPARK-33139] has two commit, include a follow up. Revert them both.
### Why are the changes needed?
Revert.
### Does this PR introduce any user-facing change?
No.
### How was this patch tested?
Existing UT.
Closes#30367 from leanken/leanken-revert-SPARK-33139.
Authored-by: xuewei.linxuewei <xuewei.linxuewei@alibaba-inc.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Update SQL migration guide for SPARK-33290
### Why are the changes needed?
Make the change better documented.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
N/A
Closes#30256 from sunchao/SPARK-33290-2.
Authored-by: Chao Sun <sunchao@apple.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
### What changes were proposed in this pull request?
Add a configuration to control the legacy behavior of whether need to pad null value when value size less then schema size.
Since we can't decide whether it's a but and some use need it behavior same as Hive.
### Why are the changes needed?
Provides a compatible choice between historical behavior and Hive
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Existed UT
Closes#30156 from AngersZhuuuu/SPARK-33284.
Lead-authored-by: angerszhu <angers.zhu@gmail.com>
Co-authored-by: AngersZhuuuu <angers.zhu@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
Return schema in SQL format instead of Catalog string from the SchemaOfCsv expression.
### Why are the changes needed?
To unify output of the `schema_of_json()` and `schema_of_csv()`.
### Does this PR introduce _any_ user-facing change?
Yes, they can but `schema_of_csv()` is usually used in combination with `from_csv()`, so, the format of schema shouldn't be much matter.
Before:
```
> SELECT schema_of_csv('1,abc');
struct<_c0:int,_c1:string>
```
After:
```
> SELECT schema_of_csv('1,abc');
STRUCT<`_c0`: INT, `_c1`: STRING>
```
### How was this patch tested?
By existing test suites `CsvFunctionsSuite` and `CsvExpressionsSuite`.
Closes#30180 from MaxGekk/schema_of_csv-sql-schema.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
Return schema in SQL format instead of Catalog string from the `SchemaOfJson` expression.
### Why are the changes needed?
In some cases, `from_json()` cannot parse schemas returned by `schema_of_json`, for instance, when JSON fields have spaces (gaps). Such fields will be quoted after the changes, and can be parsed by `from_json()`.
Here is the example:
```scala
val in = Seq("""{"a b": 1}""").toDS()
in.select(from_json('value, schema_of_json("""{"a b": 100}""")) as "parsed")
```
raises the exception:
```
== SQL ==
struct<a b:bigint>
------^^^
at org.apache.spark.sql.catalyst.parser.ParseException.withCommand(ParseDriver.scala:263)
at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parse(ParseDriver.scala:130)
at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parseTableSchema(ParseDriver.scala:76)
at org.apache.spark.sql.types.DataType$.fromDDL(DataType.scala:131)
at org.apache.spark.sql.catalyst.expressions.ExprUtils$.evalTypeExpr(ExprUtils.scala:33)
at org.apache.spark.sql.catalyst.expressions.JsonToStructs.<init>(jsonExpressions.scala:537)
at org.apache.spark.sql.functions$.from_json(functions.scala:4141)
```
### Does this PR introduce _any_ user-facing change?
Yes. For example, `schema_of_json` for the input `{"col":0}`.
Before: `struct<col:bigint>`
After: `STRUCT<`col`: BIGINT>`
### How was this patch tested?
By existing test suites `JsonFunctionsSuite` and `JsonExpressionsSuite`.
Closes#30172 from MaxGekk/schema_of_json-sql-schema.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
1. Set the default value for the SQL configs `spark.sql.legacy.parquet.int96RebaseModeInWrite` and `spark.sql.legacy.parquet.int96RebaseModeInRead` to `EXCEPTION`.
2. Update the SQL migration guide.
### Why are the changes needed?
Current default value `LEGACY` may lead to shifting timestamps in read or in write. We should leave the decision about rebasing to users.
### Does this PR introduce _any_ user-facing change?
Yes
### How was this patch tested?
By existing test suites like `ParquetIOSuite`.
Closes#30121 from MaxGekk/int96-exception-by-default.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Address comments https://github.com/apache/spark/pull/29635#discussion_r507241899 to improve migration guide
### Why are the changes needed?
improve migration guide
### Does this PR introduce _any_ user-facing change?
NO，only doc update
### How was this patch tested?
passing GitHub action
Closes#30113 from yaooqinn/SPARK-32785-F.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
### What changes were proposed in this pull request?
This PR is a sub-task of [SPARK-33138](https://issues.apache.org/jira/browse/SPARK-33138). In order to make SQLConf.get reliable and stable, we need to make sure user can't pollute the SQLConf and SparkSession Context via calling setActiveSession and clearActiveSession.
Change of the PR:
* add legacy config spark.sql.legacy.allowModifyActiveSession to fallback to old behavior if user do need to call these two API.
* by default, if user call these two API, it will throw exception
* add extra two internal and private API setActiveSessionInternal and clearActiveSessionInternal for current internal usage
* change all internal reference to new internal API except for SQLContext.setActive and SQLContext.clearActive
### Why are the changes needed?
Make SQLConf.get reliable and stable.
### Does this PR introduce any user-facing change?
No.
### How was this patch tested?
* Add UT in SparkSessionBuilderSuite to test the legacy config
* Existing test
Closes#30042 from leanken/leanken-SPARK-33139.
Authored-by: xuewei.linxuewei <xuewei.linxuewei@alibaba-inc.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
As [SPARK-13860](https://issues.apache.org/jira/browse/SPARK-13860) stated, TPCDS Query 39 returns wrong results using SparkSQL. The root cause is that when stddev_samp is applied to a single element set, with TPCDS answer, it return null; as in SparkSQL, it return Double.NaN which caused the wrong result.
Add an extra legacy config to fallback into the NaN logical, and return null by default to align with TPCDS standard.
### Why are the changes needed?
SQL correctness issue.
### Does this PR introduce any user-facing change?
Yes. See sql-migration-guide
In Spark 3.1, statistical aggregation function includes `std`, `stddev`, `stddev_samp`, `variance`, `var_samp`, `skewness`, `kurtosis`, `covar_samp`, `corr` will return `NULL` instead of `Double.NaN` when `DivideByZero` occurs during expression evaluation, for example, when `stddev_samp` applied on a single element set. In Spark version 3.0 and earlier, it will return `Double.NaN` in such case. To restore the behavior before Spark 3.1, you can set `spark.sql.legacy.statisticalAggregate` to `true`.
### How was this patch tested?
Updated DataFrameAggregateSuite/DataFrameWindowFunctionsSuite to test both default and legacy behavior.
Adjust DataFrameWindowFunctionsSuite/SQLQueryTestSuite and some R case to update to the default return null behavior.
Closes#29983 from leanken/leanken-SPARK-13860.
Authored-by: xuewei.linxuewei <xuewei.linxuewei@alibaba-inc.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
As of today,
- SPARK-30034 Apache Spark 3.0.0 switched its default Hive execution engine from Hive 1.2 to Hive 2.3. This removes the direct dependency to the forked Hive 1.2.1 in maven repository.
- SPARK-32981 Apache Spark 3.1.0(`master` branch) removed Hive 1.2 related artifacts from Apache Spark binary distributions.
This PR(SPARK-20202) aims to remove the following usage of unofficial Apache Hive fork completely from Apache Spark master for Apache Spark 3.1.0.
```
<hive.group>org.spark-project.hive</hive.group>
<hive.version>1.2.1.spark2</hive.version>
```
For the forked Hive 1.2.1.spark2 users, Apache Spark 2.4(LTS) and 3.0 (~ 2021.12) will provide it.
### Why are the changes needed?
- First, Apache Spark community should not use the unofficial forked release of another Apache project.
- Second, Apache Hive 1.2.1 was released at 2015-06-26 and the forked Hive `1.2.1.spark2` exposed many unfixable bugs in Apache because the forked `1.2.1.spark2` is not maintained at all. Apache Hive 2.3.0 was released at 2017-07-19 and it has been used with less number of bugs compared with `1.2.1.spark2`. Many bugs still exist in `hive-1.2` profile and new Apache Spark unit tests are added with `HiveUtils.isHive23` condition so far.
### Does this PR introduce _any_ user-facing change?
No. This is a dev-only change. PRBuilder will not accept `[test-hive1.2]` on master and `branch-3.1`.
### How was this patch tested?
1. SBT/Hadoop 3.2/Hive 2.3 (https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/129366)
2. SBT/Hadoop 2.7/Hive 2.3 (https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/129382)
3. SBT/Hadoop 3.2/Hive 1.2 (This has not been supported already due to Hive 1.2 doesn't work with Hadoop 3.2.)
4. SBT/Hadoop 2.7/Hive 1.2 (https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/129383, This is rejected)
Closes#29936 from dongjoon-hyun/SPARK-REMOVE-HIVE1.
Authored-by: Dongjoon Hyun <dhyun@apple.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
### What changes were proposed in this pull request?
bugfix for incomplete interval values, e.g. interval '1', interval '1 day 2', currently these cases will result null, but actually we should fail them with IllegalArgumentsException
### Why are the changes needed?
correctness
### Does this PR introduce _any_ user-facing change?
yes, incomplete intervals will throw exception now
#### before
```
bin/spark-sql -S -e "select interval '1', interval '+', interval '1 day -'"
NULL NULL NULL
```
#### after
```
-- !query
select interval '1'
-- !query schema
struct<>
-- !query output
org.apache.spark.sql.catalyst.parser.ParseException
Cannot parse the INTERVAL value: 1(line 1, pos 7)
== SQL ==
select interval '1'
```
### How was this patch tested?
unit tests added
Closes#29635 from yaooqinn/SPARK-32785.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This is a follow up PR to #29328 to apply the same constraint where `path` option cannot coexist with path parameter to `DataFrameWriter.save()`, `DataStreamReader.load()` and `DataStreamWriter.start()`.
### Why are the changes needed?
The current behavior silently overwrites the `path` option if path parameter is passed to `DataFrameWriter.save()`, `DataStreamReader.load()` and `DataStreamWriter.start()`.
For example,
```
Seq(1).toDF.write.option("path", "/tmp/path1").parquet("/tmp/path2")
```
will write the result to `/tmp/path2`.
### Does this PR introduce _any_ user-facing change?
Yes, if `path` option coexists with path parameter to any of the above methods, it will throw `AnalysisException`:
```
scala> Seq(1).toDF.write.option("path", "/tmp/path1").parquet("/tmp/path2")
org.apache.spark.sql.AnalysisException: There is a 'path' option set and save() is called with a path parameter. Either remove the path option, or call save() without the parameter. To ignore this check, set 'spark.sql.legacy.pathOptionBehavior.enabled' to 'true'.;
```
The user can restore the previous behavior by setting `spark.sql.legacy.pathOptionBehavior.enabled` to `true`.
### How was this patch tested?
Added new tests.
Closes#29543 from imback82/path_option.
Authored-by: Terry Kim <yuminkim@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This PR fixes the doc error and add a migration guide for datetime pattern.
### Why are the changes needed?
This is a bug of the doc that we inherited from JDK https://bugs.openjdk.java.net/browse/JDK-8169482
The SimpleDateFormatter(**F Day of week in month**) we used in 2.x and the DatetimeFormatter(**F week-of-month**) we use now both have the opposite meanings to what they declared in the java docs. And unfortunately, this also leads to silent data change in Spark too.
The `week-of-month` is actually the pattern `W` in DatetimeFormatter, which is banned to use in Spark 3.x.
If we want to keep pattern `F`, we need to accept the behavior change with proper migration guide and fix the doc in Spark
### Does this PR introduce _any_ user-facing change?
Yes, doc changed
### How was this patch tested?
passing ci doc generating job
Closes#29538 from yaooqinn/SPARK-32683.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This PR proposes to make the behavior consistent for the `path` option when loading dataframes with a single path (e.g, `option("path", path).format("parquet").load(path)` vs. `option("path", path).parquet(path)`) by disallowing `path` option to coexist with `load`'s path parameters.
### Why are the changes needed?
The current behavior is inconsistent:
```scala
scala> Seq(1).toDF.write.mode("overwrite").parquet("/tmp/test")
scala> spark.read.option("path", "/tmp/test").format("parquet").load("/tmp/test").show
+-----+
|value|
+-----+
| 1|
+-----+
scala> spark.read.option("path", "/tmp/test").parquet("/tmp/test").show
+-----+
|value|
+-----+
| 1|
| 1|
+-----+
```
### Does this PR introduce _any_ user-facing change?
Yes, now if the `path` option is specified along with `load`'s path parameters, it would fail:
```scala
scala> Seq(1).toDF.write.mode("overwrite").parquet("/tmp/test")
scala> spark.read.option("path", "/tmp/test").format("parquet").load("/tmp/test").show
org.apache.spark.sql.AnalysisException: There is a path option set and load() is called with path parameters. Either remove the path option or move it into the load() parameters.;
at org.apache.spark.sql.DataFrameReader.verifyPathOptionDoesNotExist(DataFrameReader.scala:310)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:232)
... 47 elided
scala> spark.read.option("path", "/tmp/test").parquet("/tmp/test").show
org.apache.spark.sql.AnalysisException: There is a path option set and load() is called with path parameters. Either remove the path option or move it into the load() parameters.;
at org.apache.spark.sql.DataFrameReader.verifyPathOptionDoesNotExist(DataFrameReader.scala:310)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:250)
at org.apache.spark.sql.DataFrameReader.parquet(DataFrameReader.scala:778)
at org.apache.spark.sql.DataFrameReader.parquet(DataFrameReader.scala:756)
... 47 elided
```
The user can restore the previous behavior by setting `spark.sql.legacy.pathOptionBehavior.enabled` to `true`.
### How was this patch tested?
Added a test
Closes#29328 from imback82/dfw_option.
Authored-by: Terry Kim <yuminkim@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Convert `NULL` elements of maps, structs and arrays to the `"null"` string while converting maps/struct/array values to strings. The SQL config `spark.sql.legacy.omitNestedNullInCast.enabled` controls the behaviour. When it is `true`, `NULL` elements of structs/maps/arrays will be omitted otherwise, when it is `false`, `NULL` elements will be converted to `"null"`.
### Why are the changes needed?
1. It is impossible to distinguish empty string and null, for instance:
```scala
scala> Seq(Seq(""), Seq(null)).toDF().show
+-----+
|value|
+-----+
| []|
| []|
+-----+
```
2. Inconsistent NULL conversions for top-level values and nested columns, for instance:
```scala
scala> sql("select named_struct('c', null), null").show
+---------------------+----+
|named_struct(c, NULL)|NULL|
+---------------------+----+
| []|null|
+---------------------+----+
```
3. `.show()` is different from conversions to Hive strings, and as a consequence its output is different from `spark-sql` (sql tests):
```sql
spark-sql> select named_struct('c', null) as struct;
{"c":null}
```
```scala
scala> sql("select named_struct('c', null) as struct").show
+------+
|struct|
+------+
| []|
+------+
```
4. It is impossible to distinguish empty struct/array from struct/array with null in the current implementation:
```scala
scala> Seq[Seq[String]](Seq(), Seq(null)).toDF.show()
+-----+
|value|
+-----+
| []|
| []|
+-----+
```
### Does this PR introduce _any_ user-facing change?
Yes, before:
```scala
scala> Seq(Seq(""), Seq(null)).toDF().show
+-----+
|value|
+-----+
| []|
| []|
+-----+
```
After:
```scala
scala> Seq(Seq(""), Seq(null)).toDF().show
+------+
| value|
+------+
| []|
|[null]|
+------+
```
### How was this patch tested?
By existing test suite `CastSuite`.
Closes#29311 from MaxGekk/nested-null-to-string.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Change casting of map and struct values to strings by using the `{}` brackets instead of `[]`. The behavior is controlled by the SQL config `spark.sql.legacy.castComplexTypesToString.enabled`. When it is `true`, `CAST` wraps maps and structs by `[]` in casting to strings. Otherwise, if this is `false`, which is the default, maps and structs are wrapped by `{}`.
### Why are the changes needed?
- To distinguish structs/maps from arrays.
- To make `show`'s output consistent with Hive and conversions to Hive strings.
- To display dataframe content in the same form by `spark-sql` and `show`
- To be consistent with the `*.sql` tests
### Does this PR introduce _any_ user-facing change?
Yes
### How was this patch tested?
By existing test suite `CastSuite`.
Closes#29308 from MaxGekk/show-struct-map.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Change _To restore the behavior before Spark **3.0**_ to _To restore the behavior before Spark **3.1**_ in the SQL migration guide while telling about the behaviour before new version 3.1.
### Why are the changes needed?
To have correct info in the SQL migration guide.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
N/A
Closes#29336 from MaxGekk/fix-version-in-sql-migration.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
When `spark.sql.caseSensitive` is `false` (by default), check that there are not duplicate column names on the same level (top level or nested levels) in reading from in-built datasources Parquet, ORC, Avro and JSON. If such duplicate columns exist, throw the exception:
```
org.apache.spark.sql.AnalysisException: Found duplicate column(s) in the data schema:
```
### Why are the changes needed?
To make handling of duplicate nested columns is similar to handling of duplicate top-level columns i. e. output the same error when `spark.sql.caseSensitive` is `false`:
```Scala
org.apache.spark.sql.AnalysisException: Found duplicate column(s) in the data schema: `camelcase`
```
Checking of top-level duplicates was introduced by https://github.com/apache/spark/pull/17758.
### Does this PR introduce _any_ user-facing change?
Yes. For the example from SPARK-32431:
ORC:
```scala
java.io.IOException: Error reading file: file:/private/var/folders/p3/dfs6mf655d7fnjrsjvldh0tc0000gn/T/spark-c02c2f9a-0cdc-4859-94fc-b9c809ca58b1/part-00001-63e8c3f0-7131-4ec9-be02-30b3fdd276f4-c000.snappy.orc
at org.apache.orc.impl.RecordReaderImpl.nextBatch(RecordReaderImpl.java:1329)
at org.apache.orc.mapreduce.OrcMapreduceRecordReader.ensureBatch(OrcMapreduceRecordReader.java:78)
...
Caused by: java.io.EOFException: Read past end of RLE integer from compressed stream Stream for column 3 kind DATA position: 6 length: 6 range: 0 offset: 12 limit: 12 range 0 = 0 to 6 uncompressed: 3 to 3
at org.apache.orc.impl.RunLengthIntegerReaderV2.readValues(RunLengthIntegerReaderV2.java:61)
at org.apache.orc.impl.RunLengthIntegerReaderV2.next(RunLengthIntegerReaderV2.java:323)
```
JSON:
```scala
+------------+
|StructColumn|
+------------+
| [,,]|
+------------+
```
Parquet:
```scala
+------------+
|StructColumn|
+------------+
| [0,, 1]|
+------------+
```
Avro:
```scala
+------------+
|StructColumn|
+------------+
| [,,]|
+------------+
```
After the changes, Parquet, ORC, JSON and Avro output the same error:
```scala
Found duplicate column(s) in the data schema: `camelcase`;
org.apache.spark.sql.AnalysisException: Found duplicate column(s) in the data schema: `camelcase`;
at org.apache.spark.sql.util.SchemaUtils$.checkColumnNameDuplication(SchemaUtils.scala:112)
at org.apache.spark.sql.util.SchemaUtils$.checkSchemaColumnNameDuplication(SchemaUtils.scala:51)
at org.apache.spark.sql.util.SchemaUtils$.checkSchemaColumnNameDuplication(SchemaUtils.scala:67)
```
### How was this patch tested?
Run modified test suites:
```
$ build/sbt "sql/test:testOnly org.apache.spark.sql.FileBasedDataSourceSuite"
$ build/sbt "avro/test:testOnly org.apache.spark.sql.avro.*"
```
and added new UT to `SchemaUtilsSuite`.
Closes#29234 from MaxGekk/nested-case-insensitive-column.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
1. Set the SQL config `spark.sql.legacy.allowCastNumericToTimestamp` to `true` by default
2. Remove explicit sets of `spark.sql.legacy.allowCastNumericToTimestamp` to `true` in the cast suites.
### Why are the changes needed?
To avoid breaking changes in minor versions (in the upcoming Spark 3.1.0) according to the the semantic versioning guidelines (https://spark.apache.org/versioning-policy.html)
### Does this PR introduce _any_ user-facing change?
Yes
### How was this patch tested?
By `CastSuite`.
Closes#29012 from MaxGekk/allow-cast-numeric-to-timestamp.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
Set the JSON option `inferTimestamp` to `false` if an user don't pass it as datasource option.
### Why are the changes needed?
To prevent perf regression while inferring schemas from JSON with potential timestamps fields.
### Does this PR introduce _any_ user-facing change?
Yes
### How was this patch tested?
- Modified existing tests in `JsonSuite` and `JsonInferSchemaSuite`.
- Regenerated results of `JsonBenchmark` in the environment:
| Item | Description |
| ---- | ----|
| Region | us-west-2 (Oregon) |
| Instance | r3.xlarge |
| AMI | ubuntu/images/hvm-ssd/ubuntu-bionic-18.04-amd64-server-20190722.1 (ami-06f2f779464715dc5) |
| Java | OpenJDK 64-Bit Server VM 1.8.0_252 and OpenJDK 64-Bit Server VM 11.0.7+10 |
Closes#28966 from MaxGekk/json-inferTimestamps-disable-by-default.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
## What changes were proposed in this pull request?
we fail casting from numeric to timestamp by default.
## Why are the changes needed?
casting from numeric to timestamp is not a non-standard,meanwhile it may generate different result between spark and other systems,for example hive
## Does this PR introduce any user-facing change?
Yes,user cannot cast numeric to timestamp directly,user have to use the following function to achieve the same effect:TIMESTAMP_SECONDS/TIMESTAMP_MILLIS/TIMESTAMP_MICROS
## How was this patch tested?
unit test added
Closes#28593 from GuoPhilipse/31710-fix-compatibility.
Lead-authored-by: GuoPhilipse <guofei_ok@126.com>
Co-authored-by: GuoPhilipse <46367746+GuoPhilipse@users.noreply.github.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Currently, `date_format` and `from_unixtime`, `unix_timestamp`,`to_unix_timestamp`, `to_timestamp`, `to_date` have different exception handling behavior for formatting datetime values.
In this PR, we apply the exception handling behavior of `date_format` to `from_unixtime`, `unix_timestamp`,`to_unix_timestamp`, `to_timestamp` and `to_date`.
In the phase of creating the datetime formatted or formating, exceptions will be raised.
e.g.
```java
spark-sql> select date_format(make_timestamp(1, 1 ,1,1,1,1), 'yyyyyyyyyyy-MM-aaa');
20/05/28 15:25:38 ERROR SparkSQLDriver: Failed in [select date_format(make_timestamp(1, 1 ,1,1,1,1), 'yyyyyyyyyyy-MM-aaa')]
org.apache.spark.SparkUpgradeException: You may get a different result due to the upgrading of Spark 3.0: Fail to recognize 'yyyyyyyyyyy-MM-aaa' pattern in the DateTimeFormatter. 1) You can set spark.sql.legacy.timeParserPolicy to LEGACY to restore the behavior before Spark 3.0. 2) You can form a valid datetime pattern with the guide from https://spark.apache.org/docs/latest/sql-ref-datetime-pattern.html
```
```java
spark-sql> select date_format(make_timestamp(1, 1 ,1,1,1,1), 'yyyyyyyyyyy-MM-AAA');
20/05/28 15:26:10 ERROR SparkSQLDriver: Failed in [select date_format(make_timestamp(1, 1 ,1,1,1,1), 'yyyyyyyyyyy-MM-AAA')]
java.lang.IllegalArgumentException: Illegal pattern character: A
```
```java
spark-sql> select date_format(make_timestamp(1,1,1,1,1,1), 'yyyyyyyyyyy-MM-dd');
20/05/28 15:23:23 ERROR SparkSQLDriver: Failed in [select date_format(make_timestamp(1,1,1,1,1,1), 'yyyyyyyyyyy-MM-dd')]
java.lang.ArrayIndexOutOfBoundsException: 11
at java.time.format.DateTimeFormatterBuilder$NumberPrinterParser.format(DateTimeFormatterBuilder.java:2568)
```
In the phase of parsing, `DateTimeParseException | DateTimeException | ParseException` will be suppressed, but `SparkUpgradeException` will still be raised
e.g.
```java
spark-sql> set spark.sql.legacy.timeParserPolicy=exception;
spark.sql.legacy.timeParserPolicy exception
spark-sql> select to_timestamp("2020-01-27T20:06:11.847-0800", "yyyy-MM-dd'T'HH:mm:ss.SSSz");
20/05/28 15:31:15 ERROR SparkSQLDriver: Failed in [select to_timestamp("2020-01-27T20:06:11.847-0800", "yyyy-MM-dd'T'HH:mm:ss.SSSz")]
org.apache.spark.SparkUpgradeException: You may get a different result due to the upgrading of Spark 3.0: Fail to parse '2020-01-27T20:06:11.847-0800' in the new parser. You can set spark.sql.legacy.timeParserPolicy to LEGACY to restore the behavior before Spark 3.0, or set to CORRECTED and treat it as an invalid datetime string.
```
```java
spark-sql> set spark.sql.legacy.timeParserPolicy=corrected;
spark.sql.legacy.timeParserPolicy corrected
spark-sql> select to_timestamp("2020-01-27T20:06:11.847-0800", "yyyy-MM-dd'T'HH:mm:ss.SSSz");
NULL
spark-sql> set spark.sql.legacy.timeParserPolicy=legacy;
spark.sql.legacy.timeParserPolicy legacy
spark-sql> select to_timestamp("2020-01-27T20:06:11.847-0800", "yyyy-MM-dd'T'HH:mm:ss.SSSz");
2020-01-28 12:06:11.847
```
### Why are the changes needed?
Consistency
### Does this PR introduce _any_ user-facing change?
Yes, invalid datetime patterns will fail `from_unixtime`, `unix_timestamp`,`to_unix_timestamp`, `to_timestamp` and `to_date` instead of resulting `NULL`
### How was this patch tested?
add more tests
Closes#28650 from yaooqinn/SPARK-31830.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
add docs for sql migration-guide
### Why are the changes needed?
let user know more about the cast scenarios in which Hive and Spark generate different results
### Does this PR introduce _any_ user-facing change?
no
### How was this patch tested?
no need to test
Closes#28605 from GuoPhilipse/spark-docs.
Lead-authored-by: GuoPhilipse <guofei_ok@126.com>
Co-authored-by: GuoPhilipse <46367746+GuoPhilipse@users.noreply.github.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
This patch effectively reverts SPARK-30098 via below changes:
* Removed the config
* Removed the changes done in parser rule
* Removed the usage of config in tests
* Removed tests which depend on the config
* Rolled back some tests to before SPARK-30098 which were affected by SPARK-30098
* Reflect the change into docs (migration doc, create table syntax)
### Why are the changes needed?
SPARK-30098 brought confusion and frustration on using create table DDL query, and we agreed about the bad effect on the change.
Please go through the [discussion thread](http://apache-spark-developers-list.1001551.n3.nabble.com/DISCUSS-Resolve-ambiguous-parser-rule-between-two-quot-create-table-quot-s-td29051i20.html) to see the details.
### Does this PR introduce _any_ user-facing change?
No, compared to Spark 2.4.x. End users tried to experiment with Spark 3.0.0 previews will see the change that the behavior is going back to Spark 2.4.x, but I believe we won't guarantee compatibility in preview releases.
### How was this patch tested?
Existing UTs.
Closes#28517 from HeartSaVioR/revert-SPARK-30098.
Authored-by: Jungtaek Lim (HeartSaVioR) <kabhwan.opensource@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This reverts commit 43a73e387c. It sets `INT96` as the timestamp type while saving timestamps to parquet files.
### Why are the changes needed?
To be compatible with Hive and Presto that don't support the `TIMESTAMP_MICROS` type in current stable releases.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
By existing test suites.
Closes#28450 from MaxGekk/parquet-int96.
Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
Fixed typo in `docs` directory and in `project/MimaExcludes.scala`
### Why are the changes needed?
Better readability of documents
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
No test needed
Closes#28447 from kiszk/typo_20200504.
Authored-by: Kazuaki Ishizaki <ishizaki@jp.ibm.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
- Rephrase the API doc for `Column.as`
- Simplify the UTs
### Why are the changes needed?
Address comments in https://github.com/apache/spark/pull/28326
### Does this PR introduce any user-facing change?
No
### How was this patch tested?
New UT added.
Closes#28390 from xuanyuanking/SPARK-27340-follow.
Authored-by: Yuanjian Li <xyliyuanjian@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This PR addresses two things:
- `SHOW TBLPROPERTIES` should supports view (a regression introduced by #26921)
- `SHOW TBLPROPERTIES` on a temporary view should return empty result (2.4 behavior instead of throwing `AnalysisException`.
### Why are the changes needed?
It's a bug.
### Does this PR introduce any user-facing change?
Yes, now `SHOW TBLPROPERTIES` works on views:
```
scala> sql("CREATE VIEW view TBLPROPERTIES('p1'='v1', 'p2'='v2') AS SELECT 1 AS c1")
scala> sql("SHOW TBLPROPERTIES view").show(truncate=false)
+---------------------------------+-------------+
|key |value |
+---------------------------------+-------------+
|view.catalogAndNamespace.numParts|2 |
|view.query.out.col.0 |c1 |
|view.query.out.numCols |1 |
|p2 |v2 |
|view.catalogAndNamespace.part.0 |spark_catalog|
|p1 |v1 |
|view.catalogAndNamespace.part.1 |default |
+---------------------------------+-------------+
```
And for a temporary view:
```
scala> sql("CREATE TEMPORARY VIEW tview TBLPROPERTIES('p1'='v1', 'p2'='v2') AS SELECT 1 AS c1")
scala> sql("SHOW TBLPROPERTIES tview").show(truncate=false)
+---+-----+
|key|value|
+---+-----+
+---+-----+
```
### How was this patch tested?
Added tests.
Closes#28375 from imback82/show_tblproperties_followup.
Authored-by: Terry Kim <yuminkim@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
Give more friendly warning message/migration guide of deprecated scala udf to users.
### Why are the changes needed?
User can not distinguish function signature between typed and untyped scala udf. Instead, we shall tell user what to do directly.
### Does this PR introduce any user-facing change?
No, it's newly added in Spark 3.0.
### How was this patch tested?
Pass Jenkins.
Closes#28311 from Ngone51/update_udf_doc.
Authored-by: yi.wu <yi.wu@databricks.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### What changes were proposed in this pull request?
**Hive 2.3.7** fixed these issues:
- HIVE-21508: ClassCastException when initializing HiveMetaStoreClient on JDK10 or newer
- HIVE-21980:Parsing time can be high in case of deeply nested subqueries
- HIVE-22249: Support Parquet through HCatalog
### Why are the changes needed?
Fix CCE during creating HiveMetaStoreClient in JDK11 environment: [SPARK-29245](https://issues.apache.org/jira/browse/SPARK-29245).
### Does this PR introduce any user-facing change?
No.
### How was this patch tested?
- [x] Test Jenkins with Hadoop 2.7 (https://github.com/apache/spark/pull/28148#issuecomment-616757840)
- [x] Test Jenkins with Hadoop 3.2 on JDK11 (https://github.com/apache/spark/pull/28148#issuecomment-616294353)
- [x] Manual test with remote hive metastore.
Hive side:
```
export JAVA_HOME=/usr/lib/jdk1.8.0_221
export PATH=$JAVA_HOME/bin:$PATH
cd /usr/lib/hive-2.3.6 # Start Hive metastore with Hive 2.3.6
bin/schematool -dbType derby -initSchema --verbose
bin/hive --service metastore
```
Spark side:
```
export JAVA_HOME=/usr/lib/jdk-11.0.3
export PATH=$JAVA_HOME/bin:$PATH
build/sbt clean package -Phive -Phadoop-3.2 -Phive-thriftserver
export SPARK_PREPEND_CLASSES=true
bin/spark-sql --conf spark.hadoop.hive.metastore.uris=thrift://localhost:9083
```
Closes#28148 from wangyum/SPARK-31381.
Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
This PR is the follow-up PR of https://github.com/apache/spark/pull/28003
- add a migration guide
- add an end-to-end test case.
### Why are the changes needed?
The original PR made the major behavior change in the user-facing RESET command.
### Does this PR introduce any user-facing change?
No
### How was this patch tested?
Added a new end-to-end test
Closes#28265 from gatorsmile/spark-31234followup.
Authored-by: gatorsmile <gatorsmile@gmail.com>
Signed-off-by: gatorsmile <gatorsmile@gmail.com>
### What changes were proposed in this pull request?
Add migration guide for extracting second from datetimes
### Why are the changes needed?
doc the behavior change for extract expression
### Does this PR introduce any user-facing change?
No
### How was this patch tested?
N/A, just passing jenkins
Closes#28140 from yaooqinn/SPARK-29311.
Authored-by: Kent Yao <yaooqinn@hotmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
This PR intends to add a new SQL config for controlling a plan explain mode in the events of (e.g., `SparkListenerSQLExecutionStart` and `SparkListenerSQLAdaptiveExecutionUpdate`) SQL listeners. In the current master, the output of `QueryExecution.toString` (this is equivalent to the "extended" explain mode) is stored in these events. I think it is useful to control the content via `SQLConf`. For example, the query "Details" content (TPCDS q66 query) of a SQL tab in a Spark web UI will be changed as follows;
Before this PR:
After this PR:
### Why are the changes needed?
For better usability.
### Does this PR introduce any user-facing change?
Yes; since Spark 3.1, SQL UI data adopts the `formatted` mode for the query plan explain results. To restore the behavior before Spark 3.0, you can set `spark.sql.ui.explainMode` to `extended`.
### How was this patch tested?
Added unit tests.
Closes#28097 from maropu/SPARK-31325.
Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Gengliang Wang <gengliang.wang@databricks.com>
### What changes were proposed in this pull request?
Based on the discussion in the mailing list [[Proposal] Modification to Spark's Semantic Versioning Policy](http://apache-spark-developers-list.1001551.n3.nabble.com/Proposal-Modification-to-Spark-s-Semantic-Versioning-Policy-td28938.html) , this PR is to add back the following APIs whose maintenance cost are relatively small.
- HiveContext
- createExternalTable APIs
### Why are the changes needed?
Avoid breaking the APIs that are commonly used.
### Does this PR introduce any user-facing change?
Adding back the APIs that were removed in 3.0 branch does not introduce the user-facing changes, because Spark 3.0 has not been released.
### How was this patch tested?
add a new test suite for createExternalTable APIs.
Closes#27815 from gatorsmile/addAPIsBack.
Lead-authored-by: gatorsmile <gatorsmile@gmail.com>
Co-authored-by: yi.wu <yi.wu@databricks.com>
Signed-off-by: gatorsmile <gatorsmile@gmail.com>
### What changes were proposed in this pull request?
Spark introduced CHAR type for hive compatibility but it only works for hive tables. CHAR type is never documented and is treated as STRING type for non-Hive tables.
However, this leads to confusing behaviors
**Apache Spark 3.0.0-preview2**
```
spark-sql> CREATE TABLE t(a CHAR(3));
spark-sql> INSERT INTO TABLE t SELECT 'a ';
spark-sql> SELECT a, length(a) FROM t;
a 2
```
**Apache Spark 2.4.5**
```
spark-sql> CREATE TABLE t(a CHAR(3));
spark-sql> INSERT INTO TABLE t SELECT 'a ';
spark-sql> SELECT a, length(a) FROM t;
a 3
```
According to the SQL standard, `CHAR(3)` should guarantee all the values are of length 3. Since `CHAR(3)` is treated as STRING so Spark doesn't guarantee it.
This PR forbids CHAR type in non-Hive tables as it's not supported correctly.
### Why are the changes needed?
avoid confusing/wrong behavior
### Does this PR introduce any user-facing change?
yes, now users can't create/alter non-Hive tables with CHAR type.
### How was this patch tested?
new tests
Closes#27902 from cloud-fan/char.
Authored-by: Wenchen Fan <wenchen@databricks.com>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
### What changes were proposed in this pull request?
https://github.com/apache/spark/pull/26412 introduced a behavior change that `date_add`/`date_sub` functions can't accept string and double values in the second parameter. This is reasonable as it's error-prone to cast string/double to int at runtime.
However, using string literals as function arguments is very common in SQL databases. To avoid breaking valid use cases that the string literal is indeed an integer, this PR proposes to add ansi_cast for string literal in date_add/date_sub functions. If the string value is not a valid integer, we fail at query compiling time because of constant folding.
### Why are the changes needed?
avoid breaking changes
### Does this PR introduce any user-facing change?
Yes, now 3.0 can run `date_add('2011-11-11', '1')` like 2.4
### How was this patch tested?
new tests.
Closes#27965 from cloud-fan/string.
Authored-by: Wenchen Fan <wenchen@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
### What changes were proposed in this pull request?
The current migration guide of SQL is too long for most readers to find the needed info. This PR is to group the items in the migration guide of Spark SQL based on the corresponding components.
Note. This PR does not change the contents of the migration guides. Attached figure is the screenshot after the change.
### Why are the changes needed?
The current migration guide of SQL is too long for most readers to find the needed info.
### Does this PR introduce any user-facing change?
No
### How was this patch tested?
N/A
Closes#27909 from gatorsmile/migrationGuideReorg.
Authored-by: gatorsmile <gatorsmile@gmail.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
