Out of all optimisations, mapping optimisation is little tricky and it will take time to implement it.
Flat File
- Optimize line sequential buffer length. Default is 1024. Based on source we need to reduce it
- Must specify column delimiter in flat files
- Optimize proper cache for XML source
Single pass reading
- Always choose there is one SQ to load data into multiple target tables
- Choose Pass-through reading to improve performance
Filters
- Use SQ to filter the Source data
- Use Filter transformation
- Always use either of one to improve performance
Optimize data type conversions
- Use Integers, wherever required in Data comparisons like Lookup/Filter
- Use “DATE” data type as String to avoid any problem
Expression
- Remove unnecessary expressions
- Observe time difference, with/without expression transformation
- Reduce multiple Lookups
- Minimize Aggregates
- Instead of the same expressions, use Local Variables
- Use always integers
- Use DECODE instead of LOOKUP
- Use operators (Ex: instead of CONCAT … use || ||) instead of functions
- Optimize IIF function. Write it in simpler way.
- Run test mapping with/without expression. Identify bottlenecks.
Related articles
- What is Informatica Mapping (informaticatipstricks.wordpress.com)
- How to rename flat file target in Informatica data synch task without losing field mapping? (stackoverflow.com)
- Informatica- Lookup Caches (srinimf.com)
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