Smart Query Acceleration Using Summaries¶

In analytical environments, most queries involve combining one or more facts tables with one or more dimensions and then, calculate an aggregation.

For these scenarios, Denodo includes smart query acceleration techniques using a new type of view called Summary. Summaries store common intermediate results that the query optimizer can then use as an starting point to accelerate analytical queries. Summaries have some advantages over the traditional cache:

1. Summaries are transparent to the user. Unlike with caching, you do not need to create a view to cache a data set. The query optimizer will automatically analyze if it can rewrite the incoming queries to take advantage of the data in the summary without the user being aware of its existence.

2. Summaries are not restricted to the data source configured for caching. This means that you can create as many summaries as you want for the same view/view in different data sources.

Creation, insertion and refreshing process are very similar to those used for remote tables. But, unlike these ones, they provide full data lineage of the views used in its definition, in the same way as a standard derived view. This allows, not only keeping the data lineage information, but also invalidating the data automatically if the definition of an underlying view changes.