IndexStat

public struct IndexStat

A structure representing statistical information about an index.

This structure provides details about the total number of entries, the count of unique values, the distribution of values, and access-related metadata for an index.

  • Properties:
    • totalCount: The total number of entries in the index.
    • uniqueValuesCount: The number of unique values in the index.
    • valueDistribution: A dictionary mapping each unique value to its occurrence count.
    • accessCount: The number of times the index has been accessed.
    • lastAccess: The date and time when the index was last accessed.

  • Undocumented

    Declaration

    Swift

    public var totalCount: Int

  • Undocumented

    Declaration

    Swift

    public var uniqueValuesCount: Int

  • Undocumented

    Declaration

    Swift

    public var valueDistribution: [AnyHashable : Int]

  • Undocumented

    Declaration

    Swift

    public var accessCount: Int

  • Undocumented

    Declaration

    Swift

    public var lastAccess: Date

  • The selectivity of the data, represented as a Double.

    Selectivity is a measure of how specific or filtered the data is, typically used in database query optimization to determine the efficiency of an index or query. A lower value indicates higher selectivity, meaning fewer rows match the criteria.

    Declaration

    Swift

    public var selectivity: Double { get }

  • Estimates the number of elements within the specified range.

    Declaration

    Swift

    public func estimateRange(lower: AnyHashable, upper: AnyHashable) -> Int

    Parameters

    lower

    The lower bound of the range as an AnyHashable value.
    upper

    The upper bound of the range as an AnyHashable value.

    Return Value

    An integer representing the estimated count of elements within the range.