Order of Writing Extracted Records to the Intermediate Files
Order of Writing Extracted Records to the Intermediate Files
When extracting data from an Oracle RAC source, the Extractor preserves the order of the SCN values for the extracted records in the intermediate files.
Prior to writing a record from an online redo thread to an intermediate file, the Extractor compares the SCN value of this record with the SCN values of the latest records from other redo threads. If records for one or more online redo threads are not available to the Extractor, the Extractor cannot compare the SCN values and process available records. The Extractor then proceeds according to the mode in which it runs:
In batch mode, the Extractor stops.
In real-time mode, the Extractor tries to determine why the records are not available so that it can continue processing.