Class CopyRowsOperation

  • All Implemented Interfaces:
    java.io.Externalizable, java.io.Serializable, Formatable, TypedFormat, Loggable, RePreparable, Undoable

    public class CopyRowsOperation
    extends PhysicalPageOperation
    Represents copying num_rows from one page to another page.
    See Also:
    Serialized Form
    Format IDLOGOP_COPY_ROWS the formatId is written by FormatIdOutputStream when this object is written out by writeObject
    Purpose
    copy some rows from one page to another
    Upgrade
    Disk LayoutPhysicalPageOperation the superclass num_rows(CompressedInt) number of rows to copy destSlot(CompressedInt) the first slot number at the destination page recordIds(CompressedInt[num_rows]) the recordIds at the destination page OptionalData the after image of the rows to be inserted into the destination page
    • Field Detail

      • num_rows

        protected int num_rows
      • destSlot

        protected int destSlot
      • recordIds

        protected int[] recordIds
      • reservedSpace

        protected int[] reservedSpace
      • preparedLog

        protected transient ByteArray preparedLog
    • Method Detail

      • writeExternal

        public void writeExternal​(java.io.ObjectOutput out)
                           throws java.io.IOException
        Specified by:
        writeExternal in interface java.io.Externalizable
        Overrides:
        writeExternal in class PageBasicOperation
        Throws:
        java.io.IOException
      • readExternal

        public void readExternal​(java.io.ObjectInput in)
                          throws java.io.IOException,
                                 java.lang.ClassNotFoundException
        Read this in
        Specified by:
        readExternal in interface java.io.Externalizable
        Overrides:
        readExternal in class PageBasicOperation
        Throws:
        java.io.IOException - error reading from log stream
        java.lang.ClassNotFoundException - log stream corrupted
      • getTypeFormatId

        public int getTypeFormatId()
        Return my format identifier.
        Returns:
        The identifier. (A UUID stuffed in an array of 16 bytes).
      • doMe

        public void doMe​(Transaction xact,
                         LogInstant instant,
                         LimitObjectInput in)
                  throws StandardException,
                         java.io.IOException
        Description copied from interface: Loggable
        Apply the change indicated by this operation and optional data. If this method fail, the system will be shut down because the log record has already been written to disk. Moreover, the log record will be replayed during recovery and this doMe method will be called on the same page again, so if it fails again, recovery will fail and the database cannot be started. So it is very important to make sure that every resource you need, such as disk space, has been acquired before the logAndDo method is called!
        This method cannot acquire any resource (like latching of a page) since it is called underneath the logging system, ie., the log record has already been written to the log stream.

        The available() method of in indicates how much data can be read, i.e. how much was originally written.

        Parameters:
        xact - the Transaction
        instant - the log instant of this operation
        in - optional data
        Throws:
        java.io.IOException - Can be thrown by any of the methods of ObjectInput.
        StandardException - Standard Derby error policy.
        See Also:
        Loggable.doMe(org.apache.derby.iapi.store.raw.Transaction, org.apache.derby.iapi.store.raw.log.LogInstant, org.apache.derby.iapi.services.io.LimitObjectInput)
      • restoreMe

        public void restoreMe​(Transaction xact,
                              BasePage undoPage,
                              LogInstant CLRInstant,
                              LimitObjectInput in)
                       throws StandardException,
                              java.io.IOException
        restore the before image of the page
        Specified by:
        restoreMe in class PageBasicOperation
        Parameters:
        xact - the Transaction doing the rollback
        undoPage - the page to rollback changes on
        CLRInstant - the log instant of this (PageUndo) operation
        in - optional data for the rollback operation
        Throws:
        java.io.IOException - problem reading the complete log record from the input stream
        StandardException - Standard Derby Error Policy
      • getPreparedLog

        public ByteArray getPreparedLog()
        Description copied from class: PageBasicOperation
        the default for optional data is set to null. If an operation has optional data, the operation need to prepare the optional data for this method. WARNING: If a log operation extends this class, and the operation has optional data, it MUST overwrite this method to return a ByteArray that contains the optional data.
        Specified by:
        getPreparedLog in interface Loggable
        Overrides:
        getPreparedLog in class PageBasicOperation
      • writeOptionalDataToBuffer

        private void writeOptionalDataToBuffer​(RawTransaction t,
                                               BasePage srcPage,
                                               int srcSlot)
                                        throws StandardException,
                                               java.io.IOException
        Write the rows that are to be copied into this page
        Throws:
        java.io.IOException - Can be thrown by any of the methods of ObjectOutput.
        StandardException - Standard Derby policy.