Database Reference
In-Depth Information
Sharing cache - named or unnamed
You can enhance performance and save the cache memory by sharing the cache if there are
multiple Lookup transformations used in a mapping. If you have the same structure for
both the Lookup transformations, sharing the cache will help enhance performance by cre-
ating the cache only once. This way, we avoid creating the cache multiple times. You can
share both named and unnamed caches.
Sharing unnamed cache
If you have multiple Lookup transformations used in a single mapping, you can share the
unnamed cache. As the Lookup transformations are present in the same mapping, naming
the cache is not mandatory. Integration Service creates the cache while processing the first
record in the first Lookup transformation and shares the cache with other lookups in the
mapping.
Sharing named cache
You can share the named cache with multiple Lookup transformations in the same mapping
or in other mappings. As the cache is named, you can assign the same cache using the
name in another mapping.
When you process the first mapping with a Lookup transformation, it saves the cache in the
defined cache directory and with the defined cache filename. When you process the second
mapping, it searches for the same location and cache file and uses the data. If Integration
Service does not find the mentioned cache file, it creates the new cache.
If you simultaneously run multiple sessions that use the same cache file, Integration Ser-
vice processes both the sessions successfully only if the Lookup transformation is con-
figured for read-only from the cache. If there is a scenario where both the Lookup trans-
formations are trying to update the cache file, or a scenario where one lookup is trying to
read the cache file and the other is trying to update the cache, the session will fail as there
is a conflict in the processing.
Sharing the cache helps enhance performance by utilizing the cache created. This way, we
save the processing time and repository space by not storing the same data for Lookup
transformations multiple times.
