Nonblocking, Partial Blocking and Blocking Transformations in SSIS

   Nonblocking, Partial Blocking and Blocking Transformations In SSIS

Transformation in SSIS lets you manipulate data during ETL(extract, transform and Load).  Operations such as aggregate, merge, split, modify,etc can be performed on data using transformations.

Transformations are generally divided into three categories as follows:

1. Non-blocking transformation: The output of this transformation uses the same buffer as that of input. It works on row by row basis. The transformation works on a synchronous basis. This transformations are efficient and lightweight results in better and faster transformation compared to other types of transformation.
2. Partial Blocking: This transformations works on a row-set basis and stores the data in buffer before releasing it to the output buffer.This transformation creates a new buffer for output rows. As this transformations generally stores some data in the buffer to perform  some operations this are generally heavy-weighted compare to Non-blocking transformations and hence performance is slower compared to Non-blocking transformation.
3.  Blocking Transformations: This transformations work on the whole data set at a time and hence stores the entire data in buffer. This transformation works on asynchronous basis.This transformation creates new buffer for output rows. consider an aggregate transformation which calculate the sum of a field in the data set, for this the transformation will have to store the entire data into buffer and then perform sum on that data set and then the results will be sent to output buffer. Because transformation stores the entire data set into the buffer, this transformations are generally the most heavy-weighted compare to other transformations and hence results in low performance. 

Following are the list of Non blocking, Partial Blocking and Blocking Transformations in SSIS