Spark学习:为Spark Sql添加自定义优化规则

一、自定义优化规则

Spark在2.2版本引入了一个强大的特性,添加钩子和拓展点,允许用户自定义优化规则
1、实现自定义规则 (静默规则，通过 set spark.sql.planChangeLog.level=WARN，确认执行到就行)

case class MyPushDown(spark: SparkSession) extends Rule[LogicalPlan] {
    
 def apply(plan: LogicalPlan): LogicalPlan = plan transform {
     .... }
}

2、创建自己的 Extension 并注入

class MySparkSessionExtension extends (SparkSessionExtensions => Unit) {
    
 override def apply(extensions: SparkSessionExtensions): Unit = {
     
  extensions.injectOptimizerRule {
     session =>
   new MyPushDown(session) 
  }
 } 
}

3、通过 spark.sql.extensions 提交

bin/spark-sql --jars my.jar --conf MySparkSessionExtension

二、代码实现

1、pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>Spark</groupId>
    <artifactId>Spark</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.12</artifactId>
            <version>3.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_2.12</artifactId>
            <version>3.2.0</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.2.2</version>
                <executions>
                    <execution>
                        <id>compile-scala</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>test-compile-scala</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>add-source</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <scalaVersion>2.12.15</scalaVersion>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.2</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <archive>
                        <manifest>
                            <mainClass></mainClass>
                        </manifest>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.6.0</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>exec</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <executable>java</executable>
                    <includeProjectDependencies>true</includeProjectDependencies>
                    <includePluginDependencies>false</includePluginDependencies>
                    <classpathScope>compile</classpathScope>
                    <mainClass>cn.spark.study.App</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

2、class

import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan
import org.apache.spark.sql.catalyst.rules.Rule

case class MyRule(spark: SparkSession) extends Rule[LogicalPlan] {
    
  logWarning("成吉思汗的规则")
  override def apply(plan: LogicalPlan): LogicalPlan = plan
}

import org.apache.spark.sql.SparkSessionExtensions

class MySparkSessionExtension extends (SparkSessionExtensions => Unit) {
    
  override def apply(extensions: SparkSessionExtensions): Unit = {
    
    extensions.injectOptimizerRule {
    
      session => MyRule(session)
    }
  }
}

3、使用maven打成jar包

三、结果验证

大功告成！完美！！！