Interface Statistics

  • All Known Implementing Classes:
    StatisticsImpl

    public interface Statistics

    This interface is used in the column SYS.SYSSTATISTICS.STATISTICS. It encapsulates information collected by the UPDATE STATISTICS command and is used internally by the Derby optimizer to estimate cost and selectivity of different query plans.

    • Method Detail

      • getRowEstimate

        long getRowEstimate()
        Returns the estimated number of rows in the index.
        Returns:
        Number of rows.
      • selectivity

        double selectivity​(java.lang.Object[] predicates)
        Returns:
        the selectivity for a set of predicates.