Thursday 18 December 2014

Change data Capture from Redo logs




The  change  data capture  has 2 approaches.  One is synchronous in which a trigger is set on the oracle table which synchronises the data into a change capture  table. This was oracle 9i change and it went away with Oracle 10 and there was asynchrounous data capture  which copies the  data from  redo log files.  In asynchronous CDC we have  two

  1. Hot log mode -- This relies on online redo logs
  2. Asynchronous mode -- this kicks in after a log switch.  So it reads from a archived redo file or a file which is not the active  redo log file


Issues using CDC…. How to do real time datawarehouse ??

What is the other way of handling CDC .. Using applicatoin level queing

Supplimental logging must be enabled for CDC  to work



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