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Four Phases of Load Operation

Posted by jyothsnav 2458 days ago (Editorial)

Four Phases of Load operation:


LOAD Phase - four things happen during the load phase; data is read from the source file specified and loaded into the appropriate target table, index key values and table statistics are collected, point of consistency information is recorded and invalid data is placed into dump files.


(LOAD QUERY command is used to monitor the progress/status of a load operation)


BUILD phase - indexes associated with primary or unique keys that have been defined for the table that was loaded are updated with the index key that have been defined for the table that was loaded are updated with the index key values that were collected and sorted during the load phase


DELETE phase - all rows that violated primary or unique key constraints on the target table are removed and copied to an exception table.


INDEX COPY phase - index data is copied from the system tempoary table space used to the tablespace where the index data associated with the table that was loaded is to reside. It is important to note this phase is executed only when LOAD command is executed with ALLOW READ ACCESS and USE (tbs) options specified.



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