What is Index Position in Cache Transformation in SSIS

 
The Cache connection manager reads a reference dataset from the Cache transform or from a cache file (.caw), and can save the data to a cache file. The data is always stored in memory.

- The Cache connection manager does not support the Binary Large Object (BLOB) data types DT_TEXT, DT_NTEXT, and DT_IMAGE




Specify which columns are index columns by specifying the index position of each column. The index is a collection of one or more columns.

For non-index columns, the index position is 0.

For index columns, the index position is a sequential, positive number. This number indicates the order in which the Lookup transformation compares rows in the reference dataset to rows in the input data source. The column with the most unique values should have the lowest index position.


The column which we specified as index Position, those all should be used as lookup search.


If you configure the cache connection manager to use a cache file, the connection manager will do one of the following actions:

- Save data to the file when a Cache Transform transformation is configured to write data from a data source in the data flow to the Cache connection manager. For more information, see Cache Transform.
- Read data from the cache file.

What's the difference between installing a "Default Instance" vs a "Named Instance"?

You can install only one default instance but can install multiple named instances.

The underlying difference between a default and named instance is mostly a matter of network connectivity. Clients can connect to the default instance using only the host name over the well-known 1433 port. To connect to a named instance, clients specify the host and instance name (e.g. "MyHost\My_Instance").

If you're only going to install one version of SQL Server on this machine, go with a default. If you're planning on multiple instances on this machine, it's up to you whether you want one named and one default, or both named.