Ssis lookup cache file

You can use source file similar to the one on the picture:. As you are done configuring the Flat File Source with all the appropriate fields definitions from the file, press OK. As the next step, you would drag-and-drop Cache Transform into the Data Flow pane. Connect Flat File Source with Cache transform, so that all the metadata is mapped between two components.

Double click the Cache's component to open its settings and click "New" button to create a new Cache Connection Manager. In the Cache Connection Manager Editor that just opened, select "Use file cache" option and browse to the file you created for the purpose of the exercise. Please, pay attention to the sensitive data warning as protection levels of the packages do not apply to the Cache component.

Click "Browse.. Now, open the Cache Transformation Editor by single clicking on the component ,navigate to the Mappings tab and connect input and destination columns:. The Lookup transformation performs lookups by joining data in input columns with columns in a reference dataset.

You use the lookup to access additional information in a related table that is based on values in common columns. The reference dataset can be a cache file, an existing table or view, a new table, or the result of an SQL query. The most commonly used cache mode is the full cache setting, and for good reason. The full cache setting has the most practical applications, and should be considered the go-to cache setting when dealing with an untested set of data. With a moderately sized set of reference data, a lookup transformation using full cache mode usually performs well.

Full cache mode does not require multiple round trips to the database, since the entire reference result set is cached prior to data flow execution.

There are a few potential gotchas to be aware of when using full cache mode. First, you can see some performance issues — memory pressure in particular — when using full cache mode against large sets of reference data.

Also, keep in mind that when doing a lookup on character data, full cache mode will always do a case-sensitive and in most cases, space-sensitive string comparison even if your database is set to a case-insensitive collation.

This is because the in-memory lookup uses a. NET string comparison which is case- and space-sensitive as opposed to a database string comparison which may be case sensitive, depending on collation. Again, neither of these present a reason to avoid full cache mode, but should be used to determine whether full cache mode should be used in a given situation. When using the partial cache setting for the SSIS lookup cache mode, lookup values will still be cached, but only as each distinct value is encountered in the data flow.

Initially, each distinct value will be retrieved individually from the specified source, and then cached. To be clear, this is a row-by-row lookup for each distinct key value s. This is a less frequently used cache setting because it addresses a narrower set of scenarios. Because each distinct key value s combination requires a relational round trip to the lookup source , performance can be an issue, especially with a large pipeline data set to be compared to the lookup data set.

This means that while you can use a RAW Source component to read the data from a cache file, you must use the Cache Transform to actually create a cache file. Unfortunately, the Cache Transform does not support incremental updates to the cache file. Each time you use it, it recreates the file completely. However, with a little creativity, you can minimize the amount of data you have to process. These are used to make the package a bit more dynamic. The LastRunDate variable controls when the package thinks it was last executed.

The LookupTable variable controls the name of the cache files. I encourage you to download the sample and walk through it to get a in-depth understanding.

Agile BI. A community for sharing ideas about business intelligence development using agile methods. Skip to content. Home About. The control flow looks like this the numbers refer to the steps below : The major components of the process are: Retrieve the last modified date from the Lookup reference table, by using an Execute SQL Task. Use a Script Task to determine if the cache file already exists.