Hello! It is a very common question, what is refresh materialized view concurrently performance effect? Let’s try to answer this question.

What is a Materialized View?

Let’s start with view. A view is a logical structure to gather data from different tables and return them as a virtual table. As said, a virtual table, which does not store any data, gathers the data from the source tables in given conditions.

A materialized view, is a view but materialized. Okay, a bad joke. But still, the main difference is materialized view stores data and retrieves data from it’s own storage.

Refreshing Materialized View

As materialized view retrieves data on creation, changes on source tables do not effect the materialized view. To reflect changes on source tables we need to refresh materialized view.

You can feel the point before i explain, as data grows, the longer time is required to refresh the materialized view. By default, materialized view is locked while refreshing it, that means, clients can not query the materialized view.

Refresh Materialized View Concurrently

To keep materialized view while refreshing we add concurrently parameter. That can be considered as a positive side but of course this also have a downside. Let’s talk about refresh materialized view concurrently performance effect.

To let users query the materialized view while refreshing it we add concurrently parameter. But it effects the performance. Especially for big data sets, it takes exponentially longer time to complete the refresh.

To add concurrently parameter, there should be at least one unique index on the materialized view.

General Information

Refreshing materialized view is a day to day operation while managing a database. You can find more information about refresh materialized view syntax, please refer to the official documentation.

Please leave a comment below, if you have questions, comments or something to add to this article. I’d like to hear your feedbacks.