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Today, I will talk to you about the role of the system library in sqlserver, which may not be well understood by many people. In order to make you understand better, the editor has summarized the following contents for you. I hope you can gain something according to this article.

SQL Server installs 4 system databases. They are master database, model database, tempdb database and msdb database.

Master database: the master database controls all aspects of SQL Server. This database includes all configuration information, user login information, and information about the process currently running on the server.

Model database: the model database is the template for creating all user databases. When you create a new database, SQL Server makes a copy of all the objects in the model database and moves them to the new database. After the template object is copied to the new user database, all excess space in the database will be filled with empty pages.

Tempdb database: tempdb database is a very special database for all users who come to access your SQL Server. This library is used to hold all temporary tables, stored procedures, and other temporary things created by SQL Server. For example, a tempdb database is used for sorting. The data is put into the tempdb database, sorted and then returned to the user. Each time SQL Server restarts, it empties the tempdb database and rebuilds it. Never create a table in an tempdb database that needs to be saved permanently.

Msdb database: msdb database is a special case of SQL Server. If you look at the actual definition of this database, you will find that it is actually a user database. The difference is what SQL Server does with this database. All task scheduling, alarms and operators are stored in the msdb database. Another function of the library is to store all backup history. SQL Server Agent will use this library.

After Log Shipping is created, the information related to Log Shipping is stored in seven tables of msdb:

Log_shipping_plans

Log_shipping_plan_databases

Log_shipping_databases

Log_shipping_plan_history

Log_shipping_monitor

Log_shipping_primaries

Log_shipping_secondaries

An error message occurs when log shipping fails to synchronize the log and update the table in the system library msdb within a predetermined time (45 minutes) when doing a system database backup.

After reading the above, do you have any further understanding of the role of system libraries in sqlserver? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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