![]() ![]() Create the scheduled event CREATE EVENT `user_stats_daily` Or start your MySQL instance with the flag –event-scheduler=ENABLED. To activate them do this SET GLOBAL event_scheduler = ON In MySQL scheduled events are not activated by default. To read more on the syntax for creating a scheduled event please read the MySQL events syntax documentation. You can schedule events to run every hour, every day, every week etc. In our case the solution is to schedule the transfer of data between the source and the “materialized view”. MySQL events are actions that you can schedule in MySQL. Method 2 – MySQL materialized views using MySQL scheduled events tweet this method for creating materialized views in mysql There are some articles out there on materialized view using triggers, but as I will show you my approach. It only makes modifications to the data when they are inserted, updated or deleted. This method offers the best performance without putting unnecessary stress on the database. The upside is that the “materialized view” will hold realtime data. You can use a smart text editor or write a small piece of code that generates the script for creating the 600 triggers.Īnother downside of this approach is that if you need to change anything in the logic of the triggers you need to re-create them. The main challenge here is to create 200 times 3 triggers. The delete trigger should identify and delete the row in the “materialized view”. The update trigger should take the updated row, identify it in the “materialized view” table and do the same update. The insert trigger should insert a copy of the inserted row in the “materialized view” table. We need to set triggers on all 3 operations (insert, update and delete) on the source tables in all 200 databases. If you are not familiar with MySQL triggers, in short they are a mechanism through which database events like inserts, updates and deletes are handled. The data is a snapshot of the data in all the 200 tables from our use case. This will both create the table and fill it in with data. To do this simply create the table using a query like: CREATE TABLE `user_stats` AS This table will be the fake “materialized view”. We will create a MySQL table with the needed structure. When any data is changed the trigger will make sure to refresh the materialized view. This method is used when you need real-time data in your materialized view. Method 1 – Create a MySQL materialized view – example using triggers tweet this method for creating materialized views in mysql ![]() There are no materialized views in MySQL, but there are ways to achieve the same results in MySQL. You cannot say CREATE MATERIALIZED VIEW `user_stats` AS CREATE MATERIALIZED VIEW Doesn’t Exist In MySQLīut, there is no MySQL syntax for creating materialized views. So, basically I needed something like a MySQL view with a cache, such that when queried it gives me the data without executing queries over 200 databases. The dashboard needed data combined from the same table in 200 different databases. The query was not very complex but it took 22 seconds to execute. Running a query over hundreds of databases every time a user goes to the dashboard was not an option. If you want to know more about the details of this read my article on handline multi-tenancy in Liferay. Each schema had the same tables and structure, but different data corresponding to a different client. The application used internally several hundreds MySQL databases (schemas). The dashboard was supposed to display statistics about an application users data. I was working on a small dashboarding project on Liferay. Let’s see an use case and how to create and use materialized views in MySQL. You don’t want the user to wait minutes to load a screen showing data, right? But if you work with huge amount of data a simple query might take minutes to execute. Having good indexes will give your MySQL view the best performance. What are materialized views? Materialized View vs View We’ll also see what are the pros and cons for these methods.īoth approaches will also work fine for creating a materialized view in MariaDB and in MySQL. In this post we will take a look at a few options for setting up materialized views in MySQL. MySQL is not the fastest relational database, but For example, you could improve a MySQL view performance simply by creating a well thought MySQL (or MariaDB) indexed view. Before turning to materialized views, you should first explore all the performance tweaks you can do to normal MySQL views. When view performance is not enough the next step is creating materialized views. You create database views for convenience and for performance. Flexviews – Real Materialized Views In MySQL.MySQL materialized views using scheduled events.MySQL materialized views using triggers.
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