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Hudi will be taking on promise for it bundles to stay compatible with Spark minor versions (for ex 2.4, 3.1, 3.2): meaning that single build of Hudi (for ex "hudi-spark3.2-bundle") will be compatible with ALL patch versions in that minor branch (in that case 3.2.1, 3.2.0, etc) To achieve that we'll have to remove (and ban) "spark-avro" as a dependency, which on a few occasions was the root-cause of incompatibility b/w consecutive Spark patch versions (most recently 3.2.1 and 3.2.0, due to this PR). Instead of bundling "spark-avro" as dependency, we will be copying over some of the classes Hudi depends on and maintain them along the Hudi code-base to make sure we're able to provide for the aforementioned guarantee. To workaround arising compatibility issues we will be applying local patches to guarantee compatibility of Hudi bundles w/in the Spark minor version branches. Following Hudi modules to Spark minor branches is currently maintained: "hudi-spark3" -> 3.2.x "hudi-spark3.1.x" -> 3.1.x "hudi-spark2" -> 2.4.x Following classes hierarchies (borrowed from "spark-avro") are maintained w/in these Spark-specific modules to guarantee compatibility with respective minor version branches: AvroSerializer AvroDeserializer AvroUtils Each of these classes has been correspondingly copied from Spark 3.2.1 (for 3.2.x branch), 3.1.2 (for 3.1.x branch), 2.4.4 (for 2.4.x branch) into their respective modules. SchemaConverters class in turn is shared across all those modules given its relative stability (there're only cosmetical changes from 2.4.4 to 3.2.1). All of the aforementioned classes have their corresponding scope of visibility limited to corresponding packages (org.apache.spark.sql.avro, org.apache.spark.sql) to make sure broader code-base does not become dependent on them and instead relies on facades abstracting them. Additionally, given that Hudi plans on supporting all the patch versions of Spark w/in aforementioned minor versions branches of Spark, additional build steps were added to validate that Hudi could be properly compiled against those versions. Testing, however, is performed against the most recent patch versions of Spark with the help of Azure CI. Brief change log: - Removing spark-avro bundling from Hudi by default - Scaffolded Spark 3.2.x hierarchy - Bootstrapped Spark 3.1.x Avro serializer/deserializer hierarchy - Bootstrapped Spark 2.4.x Avro serializer/deserializer hierarchy - Moved ExpressionCodeGen,ExpressionPayload into hudi-spark module - Fixed AvroDeserializer to stay compatible w/ both Spark 3.2.1 and 3.2.0 - Modified bot.yml to build full matrix of support Spark versions - Removed "spark-avro" dependency from all modules - Fixed relocation of spark-avro classes in bundles to assist in running integ-tests.
Description of the relationship between each module
This repo contains the code that integrate Hudi with Spark. The repo is split into the following modules
hudi-spark
hudi-spark2
hudi-spark3
hudi-spark3.1.x
hudi-spark2-common
hudi-spark3-common
hudi-spark-common
- hudi-spark is the module that contains the code that both spark2 & spark3 version would share, also contains the antlr4 file that supports spark sql on spark 2.x version.
- hudi-spark2 is the module that contains the code that compatible with spark 2.x versions.
- hudi-spark3 is the module that contains the code that compatible with spark 3.2.0(and above) versions。
- hudi-spark3.1.x is the module that contains the code that compatible with spark3.1.x and spark3.0.x version.
- hudi-spark2-common is the module that contains the code that would be reused between spark2.x versions, right now the module has no class since hudi only supports spark 2.4.4 version, and it acts as the placeholder when packaging hudi-spark-bundle module.
- hudi-spark3-common is the module that contains the code that would be reused between spark3.x versions.
- hudi-spark-common is the module that contains the code that would be reused between spark2.x and spark3.x versions.
Description of Time Travel
HoodieSpark3_2ExtendedSqlAstBuilderhave comments in the spark3.2's code fork fromorg.apache.spark.sql.catalyst.parser.AstBuilder, and additionalwithTimeTravelmethod.SqlBase.g4have comments in the code forked from spark3.2's parser, and add SparkSQL SyntaxTIMESTAMP AS OFandVERSION AS OF.
Time Travel Support Spark Version:
| version | support |
|---|---|
| 2.4.x | No |
| 3.0.x | No |
| 3.1.2 | No |
| 3.2.0 | Yes |
About upgrading Time Travel:
Spark3.3 support time travel syntax link SPARK-37219. Once Spark 3.3 released. The files in the following list will be removed:
- hudi-spark3's
HoodieSpark3_2ExtendedSqlAstBuilder.scala、HoodieSpark3_2ExtendedSqlParser.scala、TimeTravelRelation.scala、SqlBase.g4、HoodieSqlBase.g4