What a materialized view is
A materialized view is a database object that stores the results of a query physically, rather than recomputing them every time they are needed. An ordinary view is essentially a saved query that runs fresh each time it is accessed. A materialized view, by contrast, holds the actual results, so reading from it can be fast because the work has already been done.
Views versus materialized views
A standard view presents data from one or more tables as defined by a query, but it does not store the data itself; it computes the result whenever you query it. A materialized view goes further by saving the computed result. This distinction matters: the materialized view trades storage space and the need to refresh for the benefit of quick reads.
Why precomputing helps
Some queries are expensive to run, especially those that combine or summarize large amounts of data. If such a query is needed often, recomputing it every time can be slow. A materialized view precomputes and stores the result, so subsequent reads are fast. This can significantly improve performance for queries whose results are used repeatedly.
Keeping results up to date
Because a materialized view stores a snapshot of results, that stored data can become out of date as the underlying data changes. To address this, materialized views are refreshed to bring them back in line with the current data. There is a trade-off between how fresh the results are and how often the refresh happens, which is an important consideration when using them.
Where materialized views are used
Materialized views are useful where the same expensive query results are needed frequently and some delay in freshness is acceptable. They are common in reporting and analytics, where quick access to summarized data matters. By storing precomputed results, materialized views help balance performance against the cost of recomputation.
Why it matters
Materialized views are an important tool for improving query performance. Understanding what a materialized view is - a stored, precomputed query result - clarifies how databases can serve expensive queries quickly. For anyone working with databases, it is a valuable concept to understand.
Related on Skillo
See also: What is a database view? Explained, What is a database query? Explained.
Sources
Published date reflects the original event date (2025-09-30). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
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