MaterializedView 物化视图的使用(更多信息请参阅 CREATE TABLE )。它需要使用一个不同的引擎来存储数据,这个引擎要在创建物化视图时指定。当从表中读取时,它就会使用该引擎。 来源文章 January 21, ... Today’s post is a selection on snippets on Materialized Views. The materialized view for the user_id_index table stores the customer_id, user_id, and view_time of every view written to the main views table. Materialized Views, if you haven’t met them, are tables automatically populated when data is inserted into some other table. Materialized views, which store data based on remote tables are also, know as snapshots. When a master table is modified, the related materialized view becomes stale and a refresh is necessary to have the materialized view up to date. Our webinar will teach you how to use this potent tool starting with how to create materialized views and load data. MergeTree* family should be used as a storage. `.inner.a2` CREATE TABLE a1(label String) engine=Log ; CREATE MATERIALIZED VIEW a2 engine=Log as select * from a1; CREATE MATERIALIZED VIEW a3 engine=Log as select * from `.inner.a2`; CREATE MATERIALIZED VIEW a4 engine=Log as select * from `.inner.a3`; PS: don't use engine=Log as persistent storage. ... We modified our rollup/insert pipeline to store the last state written to ClickHouse when a view is resumed. Synchronous Replication. Working with Materialized View tables in ClickHouse. Why Use Materialized Views? CLICKHOUSE MATERIALIZED VIEWS A SECRET WEAPON FOR HIGH PERFORMANCE ANALYTICS Robert Hodges -- Percona Live 2018 Amsterdam 2. Presented at the webinar, June 26, 2019 Materialized views are a killer feature of ClickHouse that can speed up queries 20X or more. Materialized View inner tables. If you want to retrieve up-to-date data, then you might want to consider using a normal view or a synchronous replication. In contrary of views, materialized views avoid executing the SQL query for every access by storing the result set of the query. A materialized view in Oracle is a database object that contains the results of a query. Refreshing of Materialized Views with Indexes Hello,All of our MV's are built as completely refresh-able, on-demand, with nologging, as shown below:-CREATE MATERIALIZED VIEW mv_nameNOLOGGING TABLESPACE 'DATA_SPACE' USING INDEX TABLESPACE 'INDEX_SPACE' REFRESH ON DEMAND COMPLETE AS --SELECT Text as a What is materialized view. They are local copies of data located remotely, or are used to create summary tables based on aggregations of a table’s data. MySQL doesn't support materialized views natively, but workarounds can be implemented by using triggers or stored procedures or by using the open-source application Flexviews. I will not show you the materialized view concepts, the Oracle Datawarehouse Guide is perfect for that. 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