Class HeapCompressScan

    • Field Detail

      • pagenum_to_start_moving_rows

        private long pagenum_to_start_moving_rows
        Fields of HeapScan
    • Constructor Detail

      • HeapCompressScan

        public HeapCompressScan()
        The only constructor for a HeapCompressScan returns a scan in the closed state, the caller must call open.
    • Method Detail

      • positionAtResumeScan

        protected void positionAtResumeScan​(RowPosition pos)
                                     throws StandardException
        Reposition the scan upon entering the fetchRows loop.

        Called upon entering fetchRows() while in the SCAN_INPROGRESS state. Do work necessary to look at rows in the current page of the scan.

        The default implementation uses a record handle to maintain a scan position. It will get the latch again on the current scan position and set the slot to the current record handle.

        Overrides:
        positionAtResumeScan in class GenericScanController
        Throws:
        StandardException - Standard exception policy.
      • positionAtStartForForwardScan

        protected void positionAtStartForForwardScan​(RowPosition pos)
                                              throws StandardException
        Move the scan from SCAN_INIT to SCAN_INPROGRESS.

        This routine is called to move the scan from SCAN_INIT to SCAN_INPROGRESS. Upon return from this routine it is expected that scan_position is set such that calling the generic scan loop will reach the first row of the scan. Note that this usually means setting the scan_postion to one before the 1st row to be returned.

        Overrides:
        positionAtStartForForwardScan in class GenericScanController
        Throws:
        StandardException - Standard exception policy.
      • positionAfterThisPage

        private void positionAfterThisPage​(RowPosition pos)
                                    throws StandardException
        Set scan position to just after current page.

        Used to set the position of the scan if a record handle is not avaliable. In this case current_rh will be set to null, and current_pageno will be set to the current page number. On resume of the scan, the scan will be set to just before the first row returned form a getNextPage(current_pageno) call.

        A positionAtResumeScan(scan_position) is necessary to continue the scan after this call.

        Throws:
        StandardException - Standard exception policy.