Package org.apache.flink.runtime.state

Class KeyGroupRangeAssignment

java.lang.Object
org.apache.flink.runtime.state.KeyGroupRangeAssignment
public final class KeyGroupRangeAssignment extends Object

  • Field Details

    • DEFAULT_LOWER_BOUND_MAX_PARALLELISM

      public static final int DEFAULT_LOWER_BOUND_MAX_PARALLELISM
      The default lower bound for max parallelism if nothing was configured by the user. We have this to allow users some degree of scale-up in case they forgot to configure maximum parallelism explicitly.
      See Also:

    • UPPER_BOUND_MAX_PARALLELISM

      public static final int UPPER_BOUND_MAX_PARALLELISM
      The (inclusive) upper bound for max parallelism.
      See Also:

  • Method Details

    • assignKeyToParallelOperator

      public static int assignKeyToParallelOperator(Object key, int maxParallelism, int parallelism)
      Assigns the given key to a parallel operator index.
      Parameters:
      key - the key to assign
      maxParallelism - the maximum supported parallelism, aka the number of key-groups.
      parallelism - the current parallelism of the operator
      Returns:
      the index of the parallel operator to which the given key should be routed.

    • assignToKeyGroup

      public static int assignToKeyGroup(Object key, int maxParallelism)
      Assigns the given key to a key-group index.
      Parameters:
      key - the key to assign
      maxParallelism - the maximum supported parallelism, aka the number of key-groups.
      Returns:
      the key-group to which the given key is assigned

    • computeKeyGroupForKeyHash

      public static int computeKeyGroupForKeyHash(int keyHash, int maxParallelism)
      Assigns the given key to a key-group index.
      Parameters:
      keyHash - the hash of the key to assign
      maxParallelism - the maximum supported parallelism, aka the number of key-groups.
      Returns:
      the key-group to which the given key is assigned

    • computeKeyGroupRangeForOperatorIndex

      public static KeyGroupRange computeKeyGroupRangeForOperatorIndex(int maxParallelism, int parallelism, int operatorIndex)
      Computes the range of key-groups that are assigned to a given operator under the given parallelism and maximum parallelism.

      IMPORTANT: maxParallelism must be <= Short.MAX_VALUE + 1 to avoid rounding problems in this method. If we ever want to go beyond this boundary, this method must perform arithmetic on long values.

      Parameters:
      maxParallelism - Maximal parallelism that the job was initially created with.
      parallelism - The current parallelism under which the job runs. Must be <= maxParallelism.
      operatorIndex - index of a operatorIndex. 0 <= operatorIndex < parallelism.
      Returns:
      the computed key-group range for the operator.

    • computeOperatorIndexForKeyGroup

      public static int computeOperatorIndexForKeyGroup(int maxParallelism, int parallelism, int keyGroupId)
      Computes the index of the operator to which a key-group belongs under the given parallelism and maximum parallelism.

      IMPORTANT: maxParallelism must be <= Short.MAX_VALUE + 1 to avoid rounding problems in this method. If we ever want to go beyond this boundary, this method must perform arithmetic on long values.

      Parameters:
      maxParallelism - Maximal parallelism that the job was initially created with. 0 < parallelism <= maxParallelism <= Short.MAX_VALUE + 1 must hold.
      parallelism - The current parallelism under which the job runs. Must be <= maxParallelism.
      keyGroupId - Id of a key-group. 0 <= keyGroupID < maxParallelism.
      Returns:
      The index of the operator to which elements from the given key-group should be routed under the given parallelism and maxParallelism.

    • computeDefaultMaxParallelism

      public static int computeDefaultMaxParallelism(int operatorParallelism)
      Computes a default maximum parallelism from the operator parallelism. This is used in case the user has not explicitly configured a maximum parallelism to still allow a certain degree of scale-up.
      Parameters:
      operatorParallelism - the operator parallelism as basis for computation.
      Returns:
      the computed default maximum parallelism.

    • checkParallelismPreconditions

      public static void checkParallelismPreconditions(int parallelism)