What is the use of Merge transformation in SSIS?
Merge Transformation in SSIS is used to merge two inputs (such as tables or files) and produce one output. Merge Transformation is very useful when we want to combine the error path data (after handling the errors) and normal data.
What is IsSorted property and why do we use it?
The IsSorted property of the output that indicates whether the data has been sorted. This property must be set to True. Setting the value of the IsSorted property to True does not sort the data. This property only provides a hint to downstream components that the data has been previously sorted.
What is the prerequisite to use a Merge Join transformation?
Use the Merge Join Transformation Editor dialog box to specify the join type, the join columns, and the output columns for merging two inputs combined by a join. The Merge Join Transformation requires sorted data for its inputs.
How does Merge work in SSIS?
SSIS merge is one of the component of SSIS, available in toolbox. SSIS merge works similar way to a SQL join it merges the two or more different sources (Sources can be of same type or different type / heterogeneous) into a single output.
What is difference between Merge and Union all in SSIS?
SSIS Merge Transformation. … Merge transformation is very similar to the Union All Transformation, which combines rows from different sources into one output. The main difference is that Union All doesn’t require that the data sources are sorted, nor does its output.
Can we use merge join without sort in SSIS?
Any join operation requires a sort. This is not specific to SSIS. If you do a join in a relational database then under the covers sorting will occur.
Is sorted property in SSIS?
Your data must actually be physically sorted for the merge to work, just setting the is sorted property doesn’t actually sort the data it just provides a hint to the downstream components that it has been sorted. Both source have to be sorted by the same column.
How many data flow task can a package run in parallel?
To understand how this property works, consider the sample package with three Data Flow tasks. Each of Data Flow task contains ten source-to-destination execution trees. If you set EngineThreads to 10 on each Data Flow task, all 30 execution trees can potentially run simultaneously.
What is the difference between union and union all?
The only difference between Union and Union All is that Union extracts the rows that are being specified in the query while Union All extracts all the rows including the duplicates (repeated values) from both the queries.
What is the difference between lookup and Merge Join transformation?
The ‘Merge Join’ requires that the data be sorted before hand whereas the ‘Lookup’ doesn’t require this. Any advice would be very helpful. Thank you.