Coral

This is the code repository for the federated query optimization paper titled 'Coral: Federated Query Join Order Optimization Based on Deep Reinforcement Learning'.

This project is built on the dynamic data management framework Calcite. We implement the federated query system Coral on top of Calcite.

The detailed setup and running methods are the same as an Java application.

Prerequisites

• Git
• Java 1.8
• Hadoop 2.7.4
• Spark 2.2.4
• Maven 3.5.4
• MemSQL 7.0
• ClickHouse 19.17.3
• PostgreSQL 10.3

When installing hadoop and spark, make sure that you have basic environment variables for them, such as HADOOP_HOME, SPARK_HOME and PATH.

Please follow the installation guides to install the data engines correctly. Make sure you can that you can access all data engines through JDBC connections.

• MemSQL: https://www.digitalocean.com/community/tutorials/how-to-install-memsql-on-ubuntu-14-04
• ClickHouse: https://clickhouse.tech/docs/en/getting-started/install/
• PostgreSQL: https://www.postgresqltutorial.com/install-postgresql-linux/

In our experimental environment, the JDBC ports of MemSQL, ClickHouse, and PostgreSQL are 3309, 8123 and 5432, respectively.

Quick Start

1. Clone source code

   git clone https://github.com/PasaLab/Coral.git
   

2. Package the deep learning libary (DL4J)

   mvn clean install -Dcheckstyle.skip -DskipTests 
   

3. Build Coral

   mvn clean install -Dcheckstyle.skip -DskipTests -P coral
   

4. Start Coral

   java -cp coral.jar:dl4j.jar \
   -Dcoral.spark.master.node=<spark master> \
   -Dcoral.spark.jar.path=<path to coarl.jar> \
   -Dcoral.spark.executor.memory=15g \
   -Dcoral.conf.dir=<path to coral config directory> \
   -Dsql.logs.dir=<path to log directory> \
   -Dsql.logs.type=A2 \
   zhangyi.adapter.coral.CoralStarter
   

5. Connect to the data engines

   sqlline> !connect jdbc:calcite:model=model.json;lex=JAVA;isCacheEnable=true admin admin
   

6. Run queries in the sqlline command line

Configuration

Coral use the configuration in model.json to connect to the data engines. An example of model.json is is given below.

{
  "version": "1.0",
  "defaultSchema": "clickhouse",
  "schemas": [
    {
      "name": "postgres",
      "type": "custom",
      "factory": "org.apache.calcite.adapter.jdbc.JdbcSchema$Factory",
      "operand": {
        "jdbcUrl": "jdbc:postgresql://manager-node:5432/tpc_10",
        "jdbcUser": "postgres",
        "jdbcPassword": ""
      }
    },
    {
      "name": "clickhouse",
      "type": "custom",
      "factory": "org.apache.calcite.adapter.jdbc.JdbcSchema$Factory",
      "operand": {
        "jdbcUrl": "jdbc:clickhouse://manager-node:8123",
        "jdbcUser": "default",
        "jdbcPassword": "",
        "jdbcSchema": "tpch_10"
      }
    },
    {
      "name": "memsql",
      "type": "custom",
      "factory": "org.apache.calcite.adapter.jdbc.JdbcSchema$Factory",
      "operand": {
        "jdbcUrl": "jdbc:mysql://manager-node:3309",
        "jdbcUser": "root",
        "jdbcPassword": "",
        "jdbcCatalog": "tpc_10"
      }
    }
  ]
}

Demo

A demo video of Coral running federated queries is available on this link (video with Chinese subtitles on this link).

Copyright

The code is available for research purpose only.

For commercial usage, please contact PASA Lab@Nanjing University(gurong@nju.edu.cn).