## What changes were proposed in this pull request?
In the PR, I propose to change default behaviour of AVRO datasource which currently ignores files without `.avro` extension in read by default. This PR sets the default value for `avro.mapred.ignore.inputs.without.extension` to `false` in the case if the parameter is not set by an user.
## How was this patch tested?
Added a test file without extension in AVRO format, and new test for reading the file with and wihout specified schema.
Author: Maxim Gekk <maxim.gekk@databricks.com>
Author: Maxim Gekk <max.gekk@gmail.com>
Closes#21769 from MaxGekk/avro-without-extension.
## What changes were proposed in this pull request?
In the PR, I propose to move `testFile()` to the common trait `SQLTestUtilsBase` and wrap test files in `AvroSuite` by the method `testFile()` which returns full paths to test files in the resource folder.
Author: Maxim Gekk <maxim.gekk@databricks.com>
Closes#21773 from MaxGekk/test-file.
## What changes were proposed in this pull request?
Currently the Avro Deserializer converts input Avro format data to `Row`, and then convert the `Row` to `InternalRow`.
While the Avro Serializer converts `InternalRow` to `Row`, and then output Avro format data.
This PR allows direct conversion between `InternalRow` and Avro format data.
## How was this patch tested?
Unit test
Author: Gengliang Wang <gengliang.wang@databricks.com>
Closes#21762 from gengliangwang/avro_io.
## What changes were proposed in this pull request?
Improve Avro unit test:
1. use QueryTest/SharedSQLContext/SQLTestUtils, instead of the duplicated test utils.
2. replace deprecated methods
This is a follow up PR for #21760, the PR passes pull request tests but failed in: https://amplab.cs.berkeley.edu/jenkins/view/Spark%20QA%20Compile/job/spark-master-compile-maven-hadoop-2.6/7842/
This PR is to fix it.
## How was this patch tested?
Unit test.
Compile with different commands:
```
./build/mvn --force -DzincPort=3643 -DskipTests -Phadoop-2.6 -Phive-thriftserver -Pkinesis-asl -Pspark-ganglia-lgpl -Pmesos -Pyarn compile test-compile
./build/mvn --force -DzincPort=3643 -DskipTests -Phadoop-2.7 -Phive-thriftserver -Pkinesis-asl -Pspark-ganglia-lgpl -Pmesos -Pyarn compile test-compile
./build/mvn --force -DzincPort=3643 -DskipTests -Phadoop-3.1 -Phive-thriftserver -Pkinesis-asl -Pspark-ganglia-lgpl -Pmesos -Pyarn compile test-compile
```
Author: Gengliang Wang <gengliang.wang@databricks.com>
Closes#21768 from gengliangwang/improve_avro_test.
## What changes were proposed in this pull request?
Improve Avro unit test:
1. use QueryTest/SharedSQLContext/SQLTestUtils, instead of the duplicated test utils.
2. replace deprecated methods
## How was this patch tested?
Unit test
Author: Gengliang Wang <gengliang.wang@databricks.com>
Closes#21760 from gengliangwang/improve_avro_test.
## What changes were proposed in this pull request?
Apache Avro (https://avro.apache.org) is a popular data serialization format. It is widely used in the Spark and Hadoop ecosystem, especially for Kafka-based data pipelines. Using the external package https://github.com/databricks/spark-avro, Spark SQL can read and write the avro data. Making spark-Avro built-in can provide a better experience for first-time users of Spark SQL and structured streaming. We expect the built-in Avro data source can further improve the adoption of structured streaming.
The proposal is to inline code from spark-avro package (https://github.com/databricks/spark-avro). The target release is Spark 2.4.
[Built-in AVRO Data Source In Spark 2.4.pdf](https://github.com/apache/spark/files/2181511/Built-in.AVRO.Data.Source.In.Spark.2.4.pdf)
## How was this patch tested?
Unit test
Author: Gengliang Wang <gengliang.wang@databricks.com>
Closes#21742 from gengliangwang/export_avro.
