Package org.elasticsearch.xpack.esql.plan.logical

Class Dedup

java.lang.Object
org.elasticsearch.xpack.esql.core.tree.Node<LogicalPlan>
org.elasticsearch.xpack.esql.plan.QueryPlan<LogicalPlan>
org.elasticsearch.xpack.esql.plan.logical.LogicalPlan
org.elasticsearch.xpack.esql.plan.logical.UnaryPlan
org.elasticsearch.xpack.esql.plan.logical.Dedup
All Implemented Interfaces:
NamedWriteable, Writeable, PostAnalysisVerificationAware, TelemetryAware, Resolvable, SurrogateLogicalPlan
public class Dedup extends UnaryPlan implements SurrogateLogicalPlan, TelemetryAware, PostAnalysisVerificationAware
Removes duplicate rows from the result set (similar in spirit to SQL DISTINCT).

Implemented as a SurrogateLogicalPlan that rewrites to LIMIT 1 BY <child.output()> during the optimizer's substitutions phase. The node itself does not need to escape the coordinator, so it is not registered with the NamedWriteableRegistry.

  • Constructor Details

  • Method Details

    • replaceChild

      public Dedup replaceChild(LogicalPlan newChild)
      Specified by:
      replaceChild in class UnaryPlan

    • expressionsResolved

      public boolean expressionsResolved()
      Specified by:
      expressionsResolved in class LogicalPlan

    • info

      protected NodeInfo<Dedup> info()
      Description copied from class: Node
      Normally, you want to use one of the static create methods to implement this.

      For QueryPlans, it is very important that the properties contain all of the expressions and references relevant to this node, and that all the properties are used in the provided constructor; otherwise query plan transformations like QueryPlan#transformExpressionsOnly(Function) will not have an effect.

      Specified by:
      info in class Node<LogicalPlan>

    • telemetryLabel

      public String telemetryLabel()
      Specified by:
      telemetryLabel in interface TelemetryAware
      Returns:
      the label reported in the telemetry data. Only needs to be overwritten if the label doesn't match the class name.

    • surrogate

      public LogicalPlan surrogate()
      Description copied from interface: SurrogateLogicalPlan
      Returns the plan to be replaced with.
      Specified by:
      surrogate in interface SurrogateLogicalPlan

    • postAnalysisVerification

      public void postAnalysisVerification(Failures failures)
      Description copied from interface: PostAnalysisVerificationAware
      Allows the implementer to validate itself. This usually involves checking its internal setup, which often means checking the parameters it received on construction: their data or syntactic type, class, their count, expressions' structure etc. The discovered failures are added to the given Failures object.

      It is often more useful to perform the checks as extended as it makes sense, over stopping at the first failure. This will allow the author to progress faster to a correct query.

      Example: the Filter class, which models the WHERE command, checks that the expression it filters on - condition - is of a Boolean or NULL type: 

           
     @Override
     void postAnalysisVerification(Failures failures) {
          if (condition.dataType() != NULL && condition.dataType() != BOOLEAN) {
              failures.add(fail(condition, "Condition expression needs to be boolean, found [{}]", condition.dataType()));
          }
     }
      Specified by:
      postAnalysisVerification in interface PostAnalysisVerificationAware
      Parameters:
      failures - the object to add failures to.

    • writeTo

      public void writeTo(StreamOutput out) throws IOException
      Specified by:
      writeTo in interface Writeable
      Throws:
      IOException

    • getWriteableName

      public String getWriteableName()
      Specified by:
      getWriteableName in interface NamedWriteable