Class BTreeRowPosition

    • Field Detail

      • current_lock_row_loc

        public RowLocation current_lock_row_loc
      • parent

        private final BTreeScan parent
        The scan that owns this position object.
      • versionWhenSaved

        long versionWhenSaved
        The version number of the leaf page when this position was saved by key. Only valid if current_positionKey is non-null. This value is used to decide whether repositioning should be performed by using the key, or if RowPosition.current_rh could be used directly.
      • positionKey_template

        private DataValueDescriptor[] positionKey_template
        Cached template for saving this position by key.
      • savedFetchDescriptor

        private FetchDescriptor savedFetchDescriptor
        Cached fetch descriptor that can be used to fetch the key columns that are not already fetched by the scan. The fetch descriptor is used when this position is about to be saved by its full key.
    • Constructor Detail

      • BTreeRowPosition

        public BTreeRowPosition​(BTreeScan parent)
        Constructors for This class:
    • Method Detail

      • init

        public void init()
        Public Methods of This class:
        Overrides:
        init in class RowPosition
      • getKeyTemplate

        DataValueDescriptor[] getKeyTemplate()
                                      throws StandardException
        Get a template into which the position key can be copied. The value is cached, so two calls to this method on the same object will return the same object.
        Returns:
        an array into which the position key can be copied
        Throws:
        StandardException - if an error occurs while allocating the template array
      • getFetchDescriptorForSaveKey

        FetchDescriptor getFetchDescriptorForSaveKey​(int[] vcols,
                                                     int fullLength)
        Get a fetch descriptor that can be used to fetch the missing columns in a partial key. The fetch descriptor is only created on the first call to this method. The returned descriptor will be cached, so subsequent calls will return the same descriptor and the arguments to this method should be the same between invokations.
        Parameters:
        vcols - an array which tells which columns the partial key contains (valid columns have non-zero values in the array)
        fullLength - the length of the full key to create a fetch descriptor for (may be greater than vcols.length)
        Returns:
        a fetch descriptor
      • toString

        public final java.lang.String toString()
        Overrides:
        toString in class RowPosition