Flexviews

What is Flexviews?

Flexviews is a materialized views implementation for MariaDB, MySQL and its forks. It includes a simple SQL API that is used to create materialized views and to refresh them. The advantage of using Flexviews is that the materialized views are incrementally refreshed, that is, the views are updated efficiently by using special logs which record the changes to database tables. Flexviews includes tools which create and maintain these logs. The views created by Flexviews include support for JOINs and for all major aggregate functions.

Flexviews works well with Shard-Query, that can be used to shard the source data, making the refresh process faster.

What is a materialized view?

A “regular” view is a virtual table representing the result of a database query. Each time the view is accessed, the RDBMS must run the query to produce the result set for the view.

A materialized view is similar to regular view, except that the results are stored into an actual database table, not a virtual one. The result set is effectively cached for a period of time. When the underlying data changes the view becomes stale. Because of this, materialized views must be frequently “refreshed” to bring them up-to-date.

By caching result set data into a real table, the data can be accessed much more quickly, but at the cost of some data being potentially out-of-date. It is most useful in data warehousing scenarios, where frequent queries of the actual base tables can be extremely expensive. Since the materialized view is stored as a real table, you can build indexes on any combination of columns of the view, enabling drastic speedups in response time for queries that access the view.

MariaDB and MySQL do not support materialized views natively. Flexviews creates them as regular tables and keeps them up to date.

 

https://mariadb.com/kb/en/library/flexviews/

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