Class HeapScanInfo

  • All Implemented Interfaces:
    ScanInfo

    class HeapScanInfo
    extends java.lang.Object
    implements ScanInfo
    This object provides performance information related to an open scan. The information is accumulated during operations on a ScanController() and then copied into this object and returned by a call to ScanController.getStatistic().
    See Also:
    GenericScanController.getScanInfo()
    • Field Detail

      • stat_numpages_visited

        private int stat_numpages_visited
        Performance counters ...
      • stat_numrows_visited

        private int stat_numrows_visited
      • stat_numrows_qualified

        private int stat_numrows_qualified
      • stat_numColumnsFetched

        private int stat_numColumnsFetched
    • Constructor Detail

      • HeapScanInfo

        HeapScanInfo​(HeapScan scan)
    • Method Detail

      • getAllScanInfo

        public java.util.Properties getAllScanInfo​(java.util.Properties prop)
                                            throws StandardException
        Return all information gathered about the scan.

        This routine returns a list of properties which contains all information gathered about the scan. If a Property is passed in, then that property list is appeneded to, otherwise a new property object is created and returned.

        Not all scans may support all properties, if the property is not supported then it will not be returned. The following is a list of properties that may be returned: numPagesVisited - the number of pages visited during the scan. For btree scans this number only includes the leaf pages visited. numRowsVisited - the number of rows visited during the scan. This number includes all rows, including: those marked deleted, those that don't meet qualification, ... numRowsQualified - the number of undeleted rows, which met the qualification. treeHeight (btree's only) - for btree's the height of the tree. A tree with one page has a height of 1. Total number of pages visited in a btree scan is (treeHeight - 1 + numPagesVisited). NOTE - this list will be expanded as more information about the scan is gathered and returned.

        Specified by:
        getAllScanInfo in interface ScanInfo
        Parameters:
        prop - Property list to fill in.
        Throws:
        StandardException - Standard exception policy.