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  • Topic: Data warehousing, Data mart, Data management
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  • Published : January 23, 2013
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informatica: What r the kinds of lookup?
You can configure the Lookup transformation to perform different types of lookups. You can configure the transformation to be connected or unconnected, cached or uncached: Connected or unconnected. Connected and unconnected transformations receive input and send output in different ways. Cached or uncached. Sometimes you can improve session performance by caching the lookup table. If you cache the lookup table, you can choose to use a dynamic or static cache. By default, the lookup cache remains static and does not change during the session. With a dynamic cache, the Informatica Server inserts or updates rows in the cache during the session. When you cache the target table as the lookup, you can look up values in the target and insert them if they do not exist, or update them if they do

informatica: Persistent cache and non persistent.
PERSISTANT CACHEIf you want to save and reuse the cache files, you can configure the transformation to use a persistent cache. Use a persistent cache when you know the lookup table does not change between session runs. The first time the Informatica Server runs a session using a persistent lookup cache, it saves the cache files to disk instead of deleting them. The next time the Informatica Server runs the session, it builds the memory cache from the cache files. If the lookup table changes occasionally, you can override session properties to recache the lookup from the database. NONPERSISTANT CACHEBy default, the Informatica Server uses a non-persistent cache when you enable caching in a Lookup transformation. The Informatica Server deletes the cache files at the end of a session. The next time you run the session, the Informatica Server builds the memory cache from the database

informatica: Dynamic cache?
You might want to configure the transformation to use a dynamic cache when the target table is also the lookup table. When you use a dynamic cache, the Informatica Server updates the lookup cache as it passes rows to the target. The Informatica Server builds the cache when it processes the first lookup request. It queries the cache based on the lookup condition for each row that passes into the transformation. When the Informatica Server reads a row from the source, it updates the lookup cache by performing one of the following actions: Inserts the row into the cache. Updates the row in the cache. Makes no change to the cache.

informatica: Difference b/w filter and source qualifier?
You can use the Source Qualifier to perform the following tasks: Join data originating from the same source database. You can join two or more tables with primary-foreign key relationships by linking the sources to one Source Qualifier. Filter records when the Informatica Server reads source data. If you include a filter condition, the Informatica Server adds a WHERE clause to the default query. Specify an outer join rather than the default inner join. If you include a user-defined join, the Informatica Server replaces the join information specified by the metadata in the SQL query. Specify sorted ports. If you specify a number for sorted ports, the Informatica Server adds an ORDER BY clause to the default SQL query. Select only distinct values from the source. If you choose Select Distinct, the Informatica Server adds a SELECT DISTINCT statement to the default SQL query. Create a custom query to issue a special SELECT statement for the Informatica Server to read source data. For example, you might use a custom query to perform aggregate calculations or execute a stored procedure.

informatica:What is Data Transformation Manager Process? How many Threads it creates to process data, explain each thread in brief. When the workflow reaches a session, the Load Manager starts the DTM process. The DTM process is the process associated with the session task. The Load Manager creates one DTM process for each session in the workflow. The DTM process performs the...
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