We create a materialized view with the help of the following script. Conclusion Postgres views and materialized views are a great way to organize and view results from commonly used queries. Pass in the name of the materialized view, and the name of the view that it is based on. The query is executed and used to populate the view at the time the command is issued (unless WITH NO DATA is used) and may be refreshed later using REFRESH MATERIALIZED VIEW.. > REFRESH MATERIALIZED VIEW command to be "OBJECT_MATVIEW" so that the aclcheck > returns the appropriate error message. 创建物化视图：CREATE MATERIALIZED VIEW IF NOT EXISTS mv_t1_t2 (t1_id,t2_id, col1,col2,col3,col4,col5)ASSELECT t1.id, t2.id, t1.col1,t1.col2,t2.col3,t2.col4,t2.col5 from t1,t2where t1.id = t2.idWITH DATA; mytest=# select * from mv_t1_t2;t1_id | t2_id | col1 | col2 | col3 | col4 | col5-------+-------+------+------+------+------+------1 | 1 | a | b | c | d | e2 | 2 | a | b | c | d | e3 | 3 | a | b | c | d | e4 | 4 | a | b | c | d | e5 | 5 | a | b | c | d | e(5 rows), 刷新物化视图：mytest=# insert into t1 values (11,'x','y');mytest=# insert into t2 values (11,'x','y','z');对表进行操作，不改变物化视图中的数据。查询物化视图，数据没有改变mytest=# select * from mv_t1_t2 ;t1_id | t2_id | col1 | col2 | col3 | col4 | col5-------+-------+------+------+------+------+------1 | 1 | a | b | c | d | e2 | 2 | a | b | c | d | e3 | 3 | a | b | c | d | e4 | 4 | a | b | c | d | e5 | 5 | a | b | c | d | e(5 rows)全量更新：刷新物化视图才能使物化视图的数据改变。mytest=# REFRESH MATERIALIZED VIEW mv_t1_t2 WITH DATA;mytest=# SELECT * FROM mv_t1_t2 ;t1_id | t2_id | col1 | col2 | col3 | col4 | col5-------+-------+------+------+------+------+------1 | 1 | a | b | c | d | e2 | 2 | a | b | c | d | e3 | 3 | a | b | c | d | e4 | 4 | a | b | c | d | e5 | 5 | a | b | c | d | e11 | 11 | x | y | x | y | z(6 rows), 增量更新只有当物化视图中存在unique index的时候，refresh物化视图才能使用增量更新，加入concurrently参数。否则报错。mytest=# REFRESH MATERIALIZED VIEW CONCURRENTLY mv_t1_t2 WITH DATA;ERROR: cannot refresh materialized view "public.mv_t1_t2" concurrentlyHINT: Create a unique index with no WHERE clause on one or more columns of the materialized view.mytest=# create unique index uidx_mv_id on mv_t1_t2 (t1_id );mytest=# REFRESH MATERIALIZED VIEW CONCURRENTLY mv_t1_t2 WITH DATA;mytest=# insert into t1 values (12,'xx','yy');mytest=# insert into t2 values (12,'xx','yy','zz');mytest=# REFRESH MATERIALIZED VIEW CONCURRENTLY mv_t1_t2 WITH DATA;mytest=# select * from mv_t1_t2 ;t1_id | t2_id | col1 | col2 | col3 | col4 | col5-------+-------+------+------+------+------+------1 | 1 | a | b | c | d | e2 | 2 | a | b | c | d | e3 | 3 | a | b | c | d | e4 | 4 | a | b | c | d | e5 | 5 | a | b | c | d | e11 | 11 | x | y | x | y | z12 | 12 | xx | yy | xx | yy | zz(7 rows). The query is executed and used to populate the view at the time the command is issued (unless WITH NO DATA is used) and may be refreshed later using REFRESH MATERIALIZED VIEW.. For those of you that aren’t database experts we’re going to backup a little bit. Please note, REFRESH MATERIALIZED VIEW statement locks the query data so you cannot run queries against it. There are many things unfortunately that materialized views won't do where you are still better off with regular views. Without this option a refresh which affects a lot of rows will tend to use fewer resources and complete more quickly, but could block other connections which are trying to read from the materialized view. Refreshes a materialized view. By now, you should have two materialized views (country_total_debt, country_total_debt_2) created. The updated patch can be tested as such: > > CREATE ROLE bar LOGIN; > CREATE TABLE a (x int); > CREATE MATERIALIZED VIEW b AS SELECT * FROM a; > \c - bar > REFRESH MATERIALIZED VIEW b; > ERROR: must be owner of materialized view b > > I'm happy to generate the backpatches for it but wanted to receive feedback > first. mytest=# refresh materialized view concurrently mv_t1_t2 with data; ERROR: cannot refresh materialized view "public.mv_t1_t2" concurrently HINT: Create a unique index with no WHERE clause on one or more columns of the materialized view. You can load data into materialized view using REFRESH MATERIALIZED VIEW statement as shown. About Refresh Modes for Materialized Views. This is what I'm doing now. If WITH DATA is specified (or defaults) the backing query is executed to provide the new data, and the materialized view is left in a scannable state. One exciting new feature coming in PostgreSQL 9.3 is materialized views. It's not exactly what I wanted because the trigger fires once per statement instead of once per transaction. The above answers work fine if the materialized views do not depend on each other. If column names are not provided, they are taken from the output column names of the query. The materialized views are useful in many cases that require fast data access therefore they are often used in data warehouses or business intelligent applications. Creating materialized views In PostgreSQL, You can create a Materialized View and can refresh it. create schema matview; create schema eager; create schema lazy; PostgreSQL Materialized Views. Introduction to PostgreSQL Materialized Views. An OK solution using triggers. Matviews in PostgreSQL. All parameters supported for CREATE TABLE are also supported for CREATE MATERIALIZED VIEW with the exception of OIDS. If one row changes in the underlying table, many rows in the materialized view may be affected. The materialized view is a powerful database solution that allow us to access the view’s data faster by “caching” its response. create_matview Function. Using materialized views in the planner
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