Synchronous and Asynchronous behaviour in SSIS

Most of us have heard the terms ‘Synchronous’ and ‘Asynchronous’ in SSIS but have always been confused between the two. Let’s brush up the concepts.

All the data flow components can be categorized as synchronous and asynchronous. Below table will list out the clear differences between the two:



  1. The number of rows input to the synchronous components is equal to the number of rows output from synchronous components
  2. Components use the same buffer
  3. All destination components are synchronous
  4. Non-blocking transformations are synchronized
  1. The number of records output from Asynchronous components can be less\ more than the number of records input to the components
  2. Components use different buffer
  3. All source components are asynchronous
  4. Partial\ Full blocking transformations are asynchronous in nature

*If anyone does not have idea about non-blocking\ partial blocking\ full blocking transformations then don’t worry, just keep following my blog. Post comments if you have any queries\ like my blog.

Hope you have a good time from now.

Enjoy guys!!


One thought on “Synchronous and Asynchronous behaviour in SSIS

  1. sathish

    Differences you explained are very clear. But i’m not sure about Non-blocking,partial and full blocking. Also why don’t you explain one example for Asynchronous and Synchronous?


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