http://www.sqlservercentral.com/blogs/samvangassql/2011/11/21/ssas-processing-mode-_2800_lazy-aggregations_2900_/ Printed 2016/07/01 11:17AM
SSAS Processing Mode (Lazy Aggregations)
Processing mode property of a partition/measure group determines how partitions will be available to users.
Processing mode has two possible options.
- Regular. This is the default setting. When set to regular, partitions will be available to users after data has been loaded and aggregations are created completely.
- Lazy Aggregations. When set to lazy aggregations, partitions will be available to user queries immediately after data has been loaded. Aggregations will be created as a separate background process while users start to query the partition.
For those of you who likes technical lingo, Process Full will internally run Process Data and Process Index before the partition can be queried. If processing mode is set to Lazy Aggregations, partition will be released for user queries after Process Data is completed. Process Index will be executed in the background.
Faster availability of the partition comes with a price. Since aggregations don’t exist while users begin to query the partition they may experience slow performance.