Developer Transformation Guide > Lookup Transformation > Run-time Properties
  

Run-time Properties

Set the run-time properties to enable and configure lookup caching. You must add the Lookup transformation to a mapping before you can configure run-time lookup properties.
The following table describes run-time properties for Lookup transformations that perform flat file, reference table, or relational lookups:
Property
Description
Lookup Caching Enabled
Indicates whether the Integration Service caches lookup values.
When you enable lookup caching, the Integration Service queries the lookup source once, caches the values, and looks up values in the cache. Caching the lookup values can increase performance on large lookup tables.
When you disable caching, each time a row passes into the transformation, the Integration Service issues a select statement to the lookup source for lookup values.
The Integration Service always caches flat file lookups.
Lookup Data Cache Size
Amount of memory that the Data Integration Service allocates to the data cache for the transformation at the start of the mapping run. Select Auto to have the Data Integration Service automatically calculate the memory requirements at run time. Enter a specific value in bytes when you tune the cache size. Default is Auto.
Lookup Index Cache Size
Amount of memory that the Data Integration Service allocates to the index cache for the transformation at the start of the mapping run. Select Auto to have the Data Integration Service automatically calculate the memory requirements at run time. Enter a specific value in bytes when you tune the cache size. Default is Auto.
Cache File Name Prefix
Prefix for the cache file. You can specify the cache file name prefix for a persistent lookup cache.
Pre-build Lookup Cache
Allows the Integration Service to build the lookup cache before the Lookup transformation receives the data. The Integration Service can build multiple lookup cache files at the same time to increase performance.
Configure one of the following options:
  • - Auto. The Integration Service determines the value.
  • - Always Allowed. Allows the Integration Service to build the lookup cache before the Lookup transformation receives the data. The Integration Service can build multiple lookup cache files at the same time to increase performance.
  • - Always disallowed. The Integration Service cannot build the lookup cache before the Lookup transformation receives the first row.
Lookup Cache Directory Name
Directory used to build the lookup cache files when you configure the Lookup transformation to cache the lookup source.
Default is the CacheDir system parameter. You can configure another system parameter or user-defined parameter for this property.
Re-cache from Lookup Source
Rebuilds the lookup cache to synchronize the persistent cache with the lookup table. Recache the lookup from the database when the Lookup transformation has a persistent lookup cache and the lookup table changes occasionally.