Class SequenceRange

java.lang.Object
org.apache.derby.impl.sql.catalog.SequenceRange
All Implemented Interfaces:
SequencePreallocator
public class SequenceRange extends Object implements SequencePreallocator

Default Derby logic for determining how many values to pre-allocate for an identity column or sequence.

  • Field Details

    • DEFAULT_PREALLOCATION_COUNT

      private static final int DEFAULT_PREALLOCATION_COUNT
      Default number of values to pre-allocate. Other databases use a preallocation size of 20 (see DERBY-4437). We boosted this to 100 in order to get better concurrency, after fixing correctness problems in pre-allocation (see DERBY-5493).
      See Also:

    • _rangeSize

      private int _rangeSize
      ////////////////////////////////////////////////////////////////////////////////

  • Constructor Details

    • SequenceRange

      public SequenceRange()

      0-arg constructore needed to satisfy the SequencePreallocator contract.

    • SequenceRange

      public SequenceRange(int rangeSize)

  • Method Details

    • nextRangeSize

      public int nextRangeSize(String schemaName, String sequenceName)
      ////////////////////////////////////////////////////////////////////////////////
      Specified by:
      nextRangeSize in interface SequencePreallocator
      Parameters:
      schemaName - Name of schema holding the sequence.
      sequenceName - Specific name of the sequence.