Class StoredRecordHeader.OverflowInfo

  • Enclosing class:
    StoredRecordHeader

    private static class StoredRecordHeader.OverflowInfo
    extends java.lang.Object
    Class which holds the fields overflowId, overflowPage and firstField, which are not needed when there is no overflow. These fields are factored out to save Java heap space (see DERBY-3130).
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int firstField
      If (hasFirstField()) then this field is the number of the column in the orginal row which is now stored as the first field in this row.
      private int overflowId
      If (hasOverflow()) then this is the id of the row on page overflowPage where the next portion of the row can be found.
      private long overflowPage
      If (hasOverflow()) then this is the page where where the next portion of the row can be found.
    • Method Summary

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • overflowId

        private int overflowId
        If (hasOverflow()) then this is the id of the row on page overflowPage where the next portion of the row can be found. In this case there are no "real" fields on this page. This situation comes about if a row has been updated such that the real first field no longer fits on the head page.
      • overflowPage

        private long overflowPage
        If (hasOverflow()) then this is the page where where the next portion of the row can be found. In this case there are no "real" fields on this page.
      • firstField

        private int firstField
        If (hasFirstField()) then this field is the number of the column in the orginal row which is now stored as the first field in this row. This row is 2nd through N'th portion of a long row. For example if a row has its first 3 fields on page 0 and its next 3 fields on page 1, then the record header of the row portion on page 1 will have hasFirstField() set to true, and the value would be 4, indicating that the 4th field of the row is stored as the 1st field of the partial row portion stored on page 1.
    • Constructor Detail

      • OverflowInfo

        private OverflowInfo()
        Create an empty OverflowInfo object.