### What changes were proposed in this pull request?
This is a follow-up of https://github.com/apache/spark/pull/26780
In https://github.com/apache/spark/pull/26780, a new Avro data source option `actualSchema` is introduced for setting the original Avro schema in function `from_avro`, while the expected schema is supposed to be set in the parameter `jsonFormatSchema` of `from_avro`.
However, there is another Avro data source option `avroSchema`. It is used for setting the expected schema in readiong and writing.
This PR is to use the option `avroSchema` option for reading Avro data with an evolved schema and remove the new one `actualSchema`
### Why are the changes needed?
Unify and simplify the Avro data source options.
### Does this PR introduce any user-facing change?
Yes.
To deserialize Avro data with an evolved schema, before changes:
```
from_avro('col, expectedSchema, ("actualSchema" -> actualSchema))
```
After changes:
```
from_avro('col, actualSchema, ("avroSchema" -> expectedSchema))
```
The second parameter is always the actual Avro schema after changes.
### How was this patch tested?
Update the existing tests in https://github.com/apache/spark/pull/26780Closes#27045 from gengliangwang/renameAvroOption.
Authored-by: Gengliang Wang <gengliang.wang@databricks.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
Follow up of https://github.com/apache/spark/pull/24405
### What changes were proposed in this pull request?
The current implementation of _from_avro_ and _AvroDataToCatalyst_ doesn't allow doing schema evolution since it requires the deserialization of an Avro record with the exact same schema with which it was serialized.
The proposed change is to add a new option `actualSchema` to allow passing the schema used to serialize the records. This allows using a different compatible schema for reading by passing both schemas to _GenericDatumReader_. If no writer's schema is provided, nothing changes from before.
### Why are the changes needed?
Consider the following example.
```
// schema ID: 1
val schema1 = """
{
"type": "record",
"name": "MySchema",
"fields": [
{"name": "col1", "type": "int"},
{"name": "col2", "type": "string"}
]
}
"""
// schema ID: 2
val schema2 = """
{
"type": "record",
"name": "MySchema",
"fields": [
{"name": "col1", "type": "int"},
{"name": "col2", "type": "string"},
{"name": "col3", "type": "string", "default": ""}
]
}
"""
```
The two schemas are compatible - i.e. you can use `schema2` to deserialize events serialized with `schema1`, in which case there will be the field `col3` with the default value.
Now imagine that you have two dataframes (read from batch or streaming), one with Avro events from schema1 and the other with events from schema2. **We want to combine them into one dataframe** for storing or further processing.
With the current `from_avro` function we can only decode each of them with the corresponding schema:
```
scalaval df1 = ... // Avro events created with schema1
df1: org.apache.spark.sql.DataFrame = [eventBytes: binary]
scalaval decodedDf1 = df1.select(from_avro('eventBytes, schema1) as "decoded")
decodedDf1: org.apache.spark.sql.DataFrame = [decoded: struct<col1: int, col2: string>]
scalaval df2= ... // Avro events created with schema2
df2: org.apache.spark.sql.DataFrame = [eventBytes: binary]
scalaval decodedDf2 = df2.select(from_avro('eventBytes, schema2) as "decoded")
decodedDf2: org.apache.spark.sql.DataFrame = [decoded: struct<col1: int, col2: string, col3: string>]
```
but then `decodedDf1` and `decodedDf2` have different Spark schemas and we can't union them. Instead, with the proposed change we can decode `df1` in the following way:
```
scalaimport scala.collection.JavaConverters._
scalaval decodedDf1 = df1.select(from_avro(data = 'eventBytes, jsonFormatSchema = schema2, options = Map("actualSchema" -> schema1).asJava) as "decoded")
decodedDf1: org.apache.spark.sql.DataFrame = [decoded: struct<col1: int, col2: string, col3: string>]
```
so that both dataframes have the same schemas and can be merged.
### Does this PR introduce any user-facing change?
This PR allows users to pass a new configuration but it doesn't affect current code.
### How was this patch tested?
A new unit test was added.
Closes#26780 from Fokko/SPARK-27506.
Lead-authored-by: Fokko Driesprong <fokko@apache.org>
Co-authored-by: Gianluca Amori <gianluca.amori@gmail.com>
Signed-off-by: Gengliang Wang <gengliang.wang@databricks.com>
## What changes were proposed in this pull request?
The mapping of Spark schema to Avro schema is many-to-many. (See https://spark.apache.org/docs/latest/sql-data-sources-avro.html#supported-types-for-spark-sql---avro-conversion)
The default schema mapping might not be exactly what users want. For example, by default, a "string" column is always written as "string" Avro type, but users might want to output the column as "enum" Avro type.
With PR https://github.com/apache/spark/pull/21847, Spark supports user-specified schema in the batch writer.
For the function `to_avro`, we should support user-specified output schema as well.
## How was this patch tested?
Unit test.
Closes#25419 from gengliangwang/to_avro.
Authored-by: Gengliang Wang <gengliang.wang@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
## What changes were proposed in this pull request?
After [SPARK-26856](https://github.com/apache/spark/pull/23797), `Kinesis` Python UT fails with `Found multiple JARs` exception due to a wrong pattern.
- https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder/104171/console
```
Exception: Found multiple JARs:
.../spark-streaming-kinesis-asl-assembly-3.0.0-SNAPSHOT.jar,
.../spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT.jar;
please remove all but one
```
It's because the pattern was changed in a wrong way.
**Original**
```python
kinesis_asl_assembly_dir, "target/scala-*/%s-*.jar" % name_prefix))
kinesis_asl_assembly_dir, "target/%s_*.jar" % name_prefix))
```
**After SPARK-26856**
```python
project_full_path, "target/scala-*/%s*.jar" % jar_name_prefix))
project_full_path, "target/%s*.jar" % jar_name_prefix))
```
The actual kinesis assembly jar files look like the followings.
**SBT Build**
```
-rw-r--r-- 1 dongjoon staff 87459461 Apr 1 19:01 spark-streaming-kinesis-asl-assembly-3.0.0-SNAPSHOT.jar
-rw-r--r-- 1 dongjoon staff 309 Apr 1 18:58 spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT-tests.jar
-rw-r--r-- 1 dongjoon staff 309 Apr 1 18:58 spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT.jar
```
**MAVEN Build**
```
-rw-r--r-- 1 dongjoon staff 8.6K Apr 1 18:55 spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT-sources.jar
-rw-r--r-- 1 dongjoon staff 8.6K Apr 1 18:55 spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT-test-sources.jar
-rw-r--r-- 1 dongjoon staff 8.7K Apr 1 18:55 spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT-tests.jar
-rw-r--r-- 1 dongjoon staff 21M Apr 1 18:55 spark-streaming-kinesis-asl-assembly_2.12-3.0.0-SNAPSHOT.jar
```
In addition, after SPARK-26856, the utility function `search_jar` is shared to find `avro` jar files which are identical for both `sbt` and `mvn`. To sum up, The current jar pattern parameter cannot handle both `kinesis` and `avro` jars. This PR splits the single pattern into two patterns.
## How was this patch tested?
Manual. Please note that this will remove only `Found multiple JARs` exception. Kinesis tests need more configurations to run locally.
```
$ build/sbt -Pkinesis-asl test:package streaming-kinesis-asl-assembly/assembly
$ export ENABLE_KINESIS_TESTS=1
$ python/run-tests.py --python-executables python2.7 --module pyspark-streaming
```
Closes#24268 from dongjoon-hyun/SPARK-26856.
Authored-by: Dongjoon Hyun <dhyun@apple.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
## What changes were proposed in this pull request?
Avro is built-in but external data source module since Spark 2.4 but `from_avro` and `to_avro` APIs not yet supported in pyspark.
In this PR I've made them available from pyspark.
## How was this patch tested?
Please see the python API examples what I've added.
cd docs/
SKIP_SCALADOC=1 SKIP_RDOC=1 SKIP_SQLDOC=1 jekyll build
Manual webpage check.
Closes#23797 from gaborgsomogyi/SPARK-26856.
Authored-by: Gabor Somogyi <gabor.g.somogyi@gmail.com>
Signed-off-by: Hyukjin Kwon <gurwls223@apache.org>
