What Is a Materialized View?

Definition: Materialized View

A materialized view is a database object that contains the results of a query. It is similar to a standard view, which is a virtual table representing the results of a query, except that a materialized view is physically stored on disk, making data retrieval much faster. Materialized views are especially useful in data warehousing environments, where they speed up the process of accessing frequently queried but computationally expensive data.

Overview

Materialized views are used to optimize query performance by storing the result of a query in a physical table that can be refreshed periodically or on demand. This is particularly beneficial for queries involving complex joins, aggregations, or calculations that would otherwise need to be performed every time the query is executed. Materialized views improve performance by precomputing and storing the query result, thus avoiding the overhead of executing the query repeatedly.

Features of Materialized Views

Data Storage

Unlike standard views that dynamically retrieve data upon each query execution, materialized views store the query result directly in the database. This physical storage enables quicker data retrieval but requires additional disk space.

Query Performance

Materialized views significantly enhance query performance for complex computations. They are particularly effective in scenarios where the underlying data does not change frequently but requires heavy read operations.

Refresh Options

Materialized views can be refreshed manually, on a schedule, or triggered by changes in the underlying data. Refresh strategies can be tailored to balance between query performance and data freshness.

Dependency Management

Materialized views are dependent on the tables from which they derive their data. Database management systems keep track of these dependencies to ensure that changes in source tables can trigger updates to the materialized views as necessary.

Benefits of Materialized Views

Improved Query Performance

By storing the result of a query, materialized views reduce the time and computational overhead associated with frequently executed queries.

Timely Data Access

For applications requiring quick response times, materialized views provide a faster alternative to running complex queries on large datasets.

Efficient Data Management

Materialized views help in managing data more efficiently in scenarios where certain queries are executed frequently. They also allow for the separation of heavy computation tasks during off-peak hours by refreshing the views less frequently.

Use Cases of Materialized Views

Data Warehousing

In data warehousing, materialized views are used to precompute and store aggregate data such as sums, averages, and counts, which are frequently accessed but expensive to compute on the fly.

Reporting and Analytics

Materialized views facilitate timely and efficient reporting and analytics by storing complex query results, which can be quickly accessed by reporting tools and dashboards.

Real-time Data Aggregation

For applications that require real-time or near-real-time data aggregation, materialized views can provide an efficient solution by periodically refreshing the data to reflect the most recent updates.

Frequently Asked Questions Related to Materialized View