Shulou(Shulou.com)05/31 Report--

Editor to share with you what are the basic techniques of database recovery, I believe that most people do not know much about it, so share this article for your reference, I hope you will learn a lot after reading this article. Let's go and learn about it!

The basic techniques of database recovery are: 1, data dump; 2, register log files. Data dump is the basic technology used in database recovery. Dump is the process that DBA periodically copies the entire database to tape or another disk and saves it.

Data dump and registration log files are the basic techniques of database recovery.

Related introduction:

1. Data dump:

Data dump is the basic technology used in database recovery. Dump is the process that DBA periodically copies the entire database to tape or another disk to save. These spare data become backup copies or backup copies.

Dump can be divided into static dump and dynamic dump.

A static dump is a dump operation that occurs when there are no running transactions in the system. That is, at the beginning of the dump operation, the database is in a consistent state, and no access and modification activities to the database are allowed during the dump period. Obviously, a static dump must result in a data-consistent copy.

Dynamic dump means that the database is allowed to be accessed or modified during the dump. However, the data on the backup copy at the end of the dump is not guaranteed to be correct and valid. To this end, it is necessary to register the changes made by various transactions to the database during the dump and establish log files, so that the backup copy plus the log files can restore the database to the correct state at a certain time.

Dump can be divided into two ways: mass dump and incremental dump.

Mass dump refers to the dump of all databases at a time. Incremental dump means that only the data that has been updated since the last dump is dumped at a time. From a recovery point of view, it is generally more convenient to restore using backup copies obtained from mass dumps.

Data dump methods can be divided into four categories: dynamic incremental dump, dynamic mass dump, static incremental dump, static mass dump.

2. Register log file:

Log files are files used to record transaction updates to the database. There are two main formats of log files: log files in records and log files in blocks.

To ensure that the database is recoverable, two principles must be followed when registering log files:

The order of enlistment is strictly according to the time order in which concurrent transactions are executed.

You must write some log files before writing to the database.

The above is all the contents of the article "what are the basic techniques of database recovery". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.