Design doc for Kite Connector supporting Hbase for basic reads/ writes and DFM( delta fetch merge) if possible
JIRA: https://issues.apache.org/jira/browse/SQOOP-1744 and its sub-tickets.
Summary
Currently we have KiteConnector in Sqoop2 ( as of writing this doc) with support for writing to and reading from a HDFS dataset. The goal of SQOOP-1744 is to extend it to support reading from and writing to Hbase data set as well. An additional goal will be to support reading delta records and writing delta records from/to hbase using the Kite SDK/ APIs.
Background
There is no design or feature doc yet written for the details of the KiteConnector. Here are the relevant JIRA tickets that provide details on how the Kite FROM and Kite TO connectors work.
Kite FROM part : https://issues.apache.org/jira/browse/SQOOP-1647
Kite TO part ( for writing to HDFS via Kite ) : https://issues.apache.org/jira/browse/SQOOP-1588
Requirements
- Ability for the user to read from and write to Hbase by choosing the Kite connector, It is implementation detail if we choose to have a standalone Kite-Hbase connector reuse the KiteConnector we have today in some fashion to indicate the data set we will use
- Ability to indicate the partition strategy and column mapping for hbase data sets
- Ability to support delta reads and writes to the Hbase
- Integration tests to prove that we can move data from the JDBC to Hbase and vice versa
- Also if we can make use of Avo IDF it would avoid all the unnecessary back and forth between avro and sqoop object array types to improve the performance.
Design
Overall there are 2 ways to implementing this functionality using the KiteSDK
Option 1
Duplicate a lot of the code in KiteConnector and add a new independent connector for KiteHbaseConnector. The major con is the code duplication and effort to support Yet another connector
Option 2:
- Use the current KiteConnector and add a enum to select the type of dataset Kite will create underneath, or parse to URI given in the FromJobConfig and ToJobConfig to figure out the dataset to be HIVE/ Hbase or HDFS
public enum DataSetType { HDFS, HBASE, HIVE } // use this enum to determine what dataset kite needs to create underneath @Input public DataSetType datasetType or // parse this to figure out the data set @Input(size = 255, validators = {@Validator(DatasetURIValidator.class)}) public String uri
- Piggy back on config annotations ( conditions that we are intending to add since ages! ) to show only relevant config subsequently. For instance
hdfsHostAndPort may not be relevant for HIVE or HBase
Pros : - No code duplication
- No weird build dependency of KiteHbaseConnector depending on KiteConnector that might make independent connector upgrade complicated
Implementation Details
- Add support for Hbase related configs for column mapping and paritioning
- KiteExtractor to support creating Hbase datasets via Kite SDK and reading records
- KiteLoader to support creating Hbase datasets via Kite SDK and writing records ( merge temp data sets), this needs to be investigated more.
- How will the Hbase write happen? How different is it from HDFS write or HIVE write?
- If we support DFM, add relevant DFM configs and code in KiteConnector
Testing
Integration test suite will be enhanced to add support for the JDBC-KiteHBaseConenctor and vice versa
Performance Testing
None at this point
Open Questions
- Can we make the IDF as a config option? so that we can dynamically choose to set the IDF ( csv or avro?) Avro IDF has a great performance benefits to the Kite Connector since natively kite store avro records in memory
- Do we really independent connectors for Kite Hbase, Kite Hive, seems like a overkill to me.