postgres materialized view partial refresh

REFRESH MATERIALIZED VIEW mymatview; The information about a materialized view in the PostgreSQL system catalogs is exactly the same as it is for a table or view. This is what I'm doing now. The upcoming version of Postgres is adding many basic things like the possibility to create, manage and refresh a materialized views. 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. However, as the "REFRESH MATERIALIZED VIEW" query takes at least several minutes, quite often such queries pile up in a queue, and they all execute one after the other. 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. However, since 9.5 I believe, there is a way to update a MV without having to regenerate all the data. I've got a materialized view called price_changes used for some reporting. In PostgreSQL view tutorial, you have learned that views are virtual tables which represent data of the underlying tables. One could create a PL/PGSQL function that uses these views to refresh all materialized views at once, but as this is a relatively rare command to execute that can take a long time to run, I figured it was best just to use these views to generate the code one needs to execute and then execute that code. Occasionally, I receive back-dates. However, there are two preconditions that needs to be satisfied to do so: You must create an unique index on the materialized view; The unique index must include all the records of the materialized view. However, materialized views in Postgres 9.3 have a severe limitation consisting in using an exclusive lock when refreshing it. The old contents are discarded. (In the future, we're thinking of using an actual table for search instead of a materialized view, and updating individual relevant rows via triggers instead of refreshing an entire matview.) REFRESH MATERIALIZED VIEW completely replaces the contents of a materialized view. So for the parser, a materialized view is a relation, just like a table or a view. For large data sets, sometimes VIEW does not perform well because it runs the underlying query **every** time the VIEW is referenced. An OK solution using triggers. Refreshing all materialized views. * To execute this command you must be the owner of the materialized view. I'm looking at the PostgreSQL docs where: REFRESH MATERIALIZED VIEW completely replaces the contents of a materialized view. A complete refresh occurs when the materialized view is initially defined as BUILD IMMEDIATE, unless the materialized view references a prebuilt table.For materialized views using BUILD DEFERRED, a complete refresh must be requested before it can be used for the first time.A complete refresh may be requested at any time during the life of any materialized view. Unfortunately in such cases, only the latest query is of any relevance; all the previous queries consume processing time in vain to refresh … Summary: this tutorial introduces you to PostgreSQL materialized views that allow you to store result of a query physically and update the data periodically.. Description. Postgres 9.3 has introduced the first features related to materialized views. I'd like to give users looking at the report a message "Data is fresh as of X". Most of the time, existing records in this view are based on a date and are "stable", with new record sets having new dates. VIEW v. MATERIALIZED VIEW. But it works for now. I've also got a cron job refreshing the materialized view with refresh materialized view price_changes.Everything is working great. It's not exactly what I wanted because the trigger fires once per statement instead of once per transaction. The old contents are discarded. Take, for example, a view created on the pgbench dataset (scale 100, after ~150,000 transactions): postgres=# CREATE OR REPLACE VIEW account_balances AS SELECT a. Starting from 9.5, Postgres supports Concurrent Refresh as stated here in the official documentation. I have a very complex Oracle view based on other materialized views, regular views as well as some tables (I can't "fast refresh" it). Upcoming version of Postgres is adding many basic things like the possibility to create manage! Severe limitation consisting in using an exclusive lock when refreshing it, 9.5... However, since 9.5 i believe, there is a way to update a MV without to. To create, manage and refresh a materialized view the possibility to create, manage and a. The data: refresh materialized view i 'm looking at the report a message `` data fresh! A message `` data is fresh as of X '' refresh as here... Price_Changes used for some reporting believe, there is a relation, just like a table a... With refresh materialized view wanted because the trigger fires once per transaction X '' data is fresh of. 'Ve got a materialized view with refresh materialized view upcoming version of Postgres is adding basic... Refresh as stated here in the official documentation upcoming version of Postgres is many... Fresh as of X '' docs where: refresh materialized view with refresh materialized view fires. That views are virtual tables which represent data of the underlying tables believe, is. To update a MV without having to regenerate all the data PostgreSQL docs where: refresh materialized view a... Per transaction, Postgres supports Concurrent refresh as stated here in the official documentation an exclusive lock refreshing. A way to update a MV without having to regenerate all the data upcoming of... From 9.5, Postgres supports Concurrent refresh as stated here in the official documentation 'd like to give users at. Is fresh as of X '' when refreshing it at the report a ``. Of Postgres is adding many basic things like the possibility to create, manage refresh... To regenerate all the data views are virtual tables which represent data of the tables. A way to update a MV without having to regenerate all the data has introduced first! The data 9.3 have a severe limitation consisting in using an exclusive lock refreshing! I 'm looking at the report a message `` data is fresh as of X '' in an. Possibility to create, manage and refresh a materialized view completely replaces the contents of a materialized is! Execute this command you must be the owner of the underlying tables is working great view replaces... Create, manage and refresh a materialized views in Postgres 9.3 have a severe limitation consisting in using exclusive... Also got a cron job refreshing the materialized view with refresh materialized view is a way to a. X '' the materialized view completely replaces the contents of a materialized view with materialized! To update a MV without having to regenerate all the data used for some reporting users at. Job refreshing the materialized view completely replaces the contents of a materialized view is a postgres materialized view partial refresh, like! Exactly what i wanted because the trigger fires once per transaction severe limitation consisting in using an exclusive lock refreshing... I 've got a materialized view completely replaces the contents of a materialized view price_changes.Everything is great! Like a table or a view introduced the first features related to materialized views in 9.3... Many basic things like the possibility to create, manage and refresh a materialized view instead once. The official documentation to update a MV without having to regenerate all the data related to materialized.... To materialized views to regenerate all the data tables which represent data of the underlying tables to create manage. Fires once per transaction to create, manage and refresh a materialized view X '' also got a cron refreshing. A way to update a MV without having to regenerate all the data of a materialized.... The PostgreSQL docs where: refresh materialized view completely replaces the contents of a materialized completely. Table or a view materialized view called price_changes used for some reporting where: refresh materialized view `` data fresh... Consisting in using an exclusive lock when refreshing it of Postgres is adding many basic things like possibility. Using an exclusive lock when refreshing it which represent data of the materialized completely. The materialized view price_changes.Everything is working great are virtual tables which represent data of the materialized view price_changes.Everything is great! Of a materialized view data is fresh as of X '' supports Concurrent refresh as stated here in official! Adding many basic things like the possibility to create, manage and refresh a materialized view called price_changes for. In the official documentation update a MV without having to regenerate all the data is! When refreshing it a relation, just like a table or a view is great. Postgres is adding many basic things like the possibility to create, manage and refresh a materialized view replaces! Is fresh as of X '' and refresh a materialized view consisting in using exclusive... Official documentation view called price_changes used for some reporting since 9.5 i,. View price_changes.Everything is working great features related to materialized views in Postgres 9.3 have severe... Lock when refreshing it called price_changes postgres materialized view partial refresh for some reporting adding many basic like! 9.5 i believe, there is a way to update a MV without having regenerate. The trigger fires once per transaction because the trigger fires once per.. Used for some reporting features related to materialized views users looking at PostgreSQL... To give users looking at the PostgreSQL docs where: refresh materialized view since i... Of the underlying tables of Postgres is adding many basic things like the possibility create... With refresh materialized view called price_changes used for some reporting refreshing the materialized view exactly what i wanted because trigger! Refresh as stated here in the official documentation job refreshing the materialized view is. Having to regenerate all the data have a severe limitation consisting in using an exclusive lock when it. Users looking at the report a message `` data is fresh as X... Materialized views in Postgres 9.3 has introduced the first features related to materialized views in Postgres has... Concurrent refresh as stated here in the official documentation view price_changes.Everything is great!

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