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org.apache.spark.sql

SparkSessionExtensions

class SparkSessionExtensions extends AnyRef

ExperimentalDeveloper API

Holder for injection points to the SparkSession. We make NO guarantee about the stability regarding binary compatibility and source compatibility of methods here.

This current provides the following extension points:

  • Analyzer Rules.
  • Check Analysis Rules.
  • Optimizer Rules.
  • Pre CBO Rules.
  • Planning Strategies.
  • Customized Parser.
  • (External) Catalog listeners.
  • Columnar Rules.
  • Adaptive Query Stage Preparation Rules.
  • Adaptive Query Execution Runtime Optimizer Rules.

The extensions can be used by calling withExtensions on the SparkSession.Builder, for example:

SparkSession.builder()
  .master("...")
  .config("...", true)
  .withExtensions { extensions =>
    extensions.injectResolutionRule { session =>
      ...
    }
    extensions.injectParser { (session, parser) =>
      ...
    }
  }
  .getOrCreate()

The extensions can also be used by setting the Spark SQL configuration property spark.sql.extensions. Multiple extensions can be set using a comma-separated list. For example:

SparkSession.builder()
  .master("...")
  .config("spark.sql.extensions", "org.example.MyExtensions,org.example.YourExtensions")
  .getOrCreate()

class MyExtensions extends Function1[SparkSessionExtensions, Unit] {
  override def apply(extensions: SparkSessionExtensions): Unit = {
    extensions.injectResolutionRule { session =>
      ...
    }
    extensions.injectParser { (session, parser) =>
      ...
    }
  }
}

class YourExtensions extends SparkSessionExtensionsProvider {
  override def apply(extensions: SparkSessionExtensions): Unit = {
    extensions.injectResolutionRule { session =>
      ...
    }
    extensions.injectFunction(...)
  }
}

Note that none of the injected builders should assume that the SparkSession is fully initialized and should not touch the session's internals (e.g. the SessionState).

Annotations
@DeveloperApi() @Experimental() @Unstable()
Source
SparkSessionExtensions.scala
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Instance Constructors

  1. new SparkSessionExtensions()

Type Members

  1. type CheckRuleBuilder = (SparkSession) ⇒ (LogicalPlan) ⇒ Unit
  2. type ColumnarRuleBuilder = (SparkSession) ⇒ ColumnarRule
  3. type FunctionDescription = (FunctionIdentifier, ExpressionInfo, FunctionBuilder)
  4. type ParserBuilder = (SparkSession, ParserInterface) ⇒ ParserInterface
  5. type QueryStagePrepRuleBuilder = (SparkSession) ⇒ Rule[SparkPlan]
  6. type RuleBuilder = (SparkSession) ⇒ Rule[LogicalPlan]
  7. type StrategyBuilder = (SparkSession) ⇒ Strategy
  8. type TableFunctionDescription = (FunctionIdentifier, ExpressionInfo, TableFunctionBuilder)

Value Members

  1. def injectCheckRule(builder: CheckRuleBuilder): Unit

    Inject an check analysis Rule builder into the SparkSession.

    Inject an check analysis Rule builder into the SparkSession. The injected rules will be executed after the analysis phase. A check analysis rule is used to detect problems with a LogicalPlan and should throw an exception when a problem is found.

  2. def injectColumnar(builder: ColumnarRuleBuilder): Unit

    Inject a rule that can override the columnar execution of an executor.

  3. def injectFunction(functionDescription: FunctionDescription): Unit

    Injects a custom function into the org.apache.spark.sql.catalyst.analysis.FunctionRegistry at runtime for all sessions.

  4. def injectOptimizerRule(builder: RuleBuilder): Unit

    Inject an optimizer Rule builder into the SparkSession.

    Inject an optimizer Rule builder into the SparkSession. The injected rules will be executed during the operator optimization batch. An optimizer rule is used to improve the quality of an analyzed logical plan; these rules should never modify the result of the LogicalPlan.

  5. def injectParser(builder: ParserBuilder): Unit

    Inject a custom parser into the SparkSession.

    Inject a custom parser into the SparkSession. Note that the builder is passed a session and an initial parser. The latter allows for a user to create a partial parser and to delegate to the underlying parser for completeness. If a user injects more parsers, then the parsers are stacked on top of each other.

  6. def injectPlannerStrategy(builder: StrategyBuilder): Unit

    Inject a planner Strategy builder into the SparkSession.

    Inject a planner Strategy builder into the SparkSession. The injected strategy will be used to convert a LogicalPlan into a executable org.apache.spark.sql.execution.SparkPlan.

  7. def injectPostHocResolutionRule(builder: RuleBuilder): Unit

    Inject an analyzer Rule builder into the SparkSession.

    Inject an analyzer Rule builder into the SparkSession. These analyzer rules will be executed after resolution.

  8. def injectPreCBORule(builder: RuleBuilder): Unit

    Inject an optimizer Rule builder that rewrites logical plans into the SparkSession.

    Inject an optimizer Rule builder that rewrites logical plans into the SparkSession. The injected rules will be executed once after the operator optimization batch and before any cost-based optimization rules that depend on stats.

  9. def injectQueryStagePrepRule(builder: QueryStagePrepRuleBuilder): Unit

    Inject a rule that can override the query stage preparation phase of adaptive query execution.

  10. def injectResolutionRule(builder: RuleBuilder): Unit

    Inject an analyzer resolution Rule builder into the SparkSession.

    Inject an analyzer resolution Rule builder into the SparkSession. These analyzer rules will be executed as part of the resolution phase of analysis.

  11. def injectRuntimeOptimizerRule(builder: RuleBuilder): Unit

    Inject a runtime Rule builder into the SparkSession.

    Inject a runtime Rule builder into the SparkSession. The injected rules will be executed after built-in org.apache.spark.sql.execution.adaptive.AQEOptimizer rules are applied. A runtime optimizer rule is used to improve the quality of a logical plan during execution which can leverage accurate statistics from shuffle.

    Note that, it does not work if adaptive query execution is disabled.

  12. def injectTableFunction(functionDescription: TableFunctionDescription): Unit

    Injects a custom function into the org.apache.spark.sql.catalyst.analysis.TableFunctionRegistry at runtime for all sessions.