MySQL Backup and recovery

Discusses MySQL backup and recovery mechanisms, and how to maintain data tables, including the two most important types of tables: MyISAM and Innodb, the version of MySQL designed in this article is 5.0.22.

This article describes the use of MySQL with a free backup tool backup, of course you can choose some more convenient third-party tools for backup and restore the MySQL database.

The free backup tools currently supported by MySQL are: mysqldump, mysqlhotcopy, and can be backed up with SQL syntax: Backup TABLE or Select into outfile, or backup binary log (binlog), It can also be a direct copy of the data file and the associated configuration file. MyISAM tables are stored in the form of files, so they are relatively easy to back up, and several of the above mentioned methods are available. Innodb All tables are stored in the same data file ibdata1 (or multiple files, or separate tablespace files), relatively difficult to backup, the free scheme can be copied data files, backup Binlog, or with mysqldump.

1, mysqldump

1.1 Backup

Mysqldump is a SQL-level backup mechanism that guides data tables into SQL script files and is relatively appropriate for upgrades between different versions of MySQL, which is also the most common method of backup.

Now let's talk about some of the main parameters of mysqldump:

--compatible=name

It tells Mysqldump which database or older version of the MySQL server the exported data will be compatible with. Values can be ANSI, mysql323, MYSQL40, PostgreSQL, Oracle, MSSQL, DB2, MAXDB, No_key_options, no_tables_options, no_field_options, etc. , you use a few values to separate them with commas. Of course, it does not guarantee full compatibility, but is as compatible as possible.

--complete-insert,-c

The exported data takes a complete Insert with the field name, which means that all values are written on one line. This can increase the efficiency of the insertion, but may be affected by the Max_allowed_packet parameter and cause the insertion to fail. Therefore, you need to use this parameter with caution, at least I do not recommend it.

--default-character-set=charset

Specifies what character set to use when exporting data, and if the datasheet is not the default Latin1 character set, you must specify this option when exporting, otherwise the garbled problem will occur after you import the data again.

--disable-keys

Tell mysqldump to add/*!40000 Alter table Table DISABLE KEYS at the beginning and end of the Insert statement. and/*!40000 Alter table table to ENABLE the KEYS * *; statement, which greatly increases the speed of the INSERT statement because it rebuilds the index after all the data has been inserted. This option is only suitable for MyISAM tables.

--extended-insert = True|false

By default, Mysqldump opens the--complete-insert mode, so if you don't want to use it, use this option to set its value to false.

--hex-blob

Exports a binary string field using hexadecimal format. You must use this option if you have binary data. The field types that are affected are BINARY, VARBINARY, and blobs.

--lock-all-tables,-x

Commit the request to lock all tables in all databases before starting the export to ensure data consistency. This is a global read lock and automatically turns off the--single-transaction and--lock-tables options.

--lock-tables

Similar to--lock-all-tables, it locks the currently exported datasheet instead of locking the table under all the libraries at once. This option applies only to MyISAM tables, and if the Innodb table can use the--single-transaction option.

--no-create-info,-t

Exports only data without adding a Create TABLE statement.

--no-data,-d

Does not export any data, only the database table structure is exported.

--opt

This is just a shortcut option, equivalent to adding--add-drop-tables--add-locking--create-option--disable-keys--extended-insert--lock-tables- Quick--set-charset option. This option allows mysqldump to quickly export data, and the exported data can be quickly returned. This option is turned on by default, but can be disabled with--skip-opt. Note that if you run mysqldump without specifying the--quick or--opt option, the entire result set is placed in memory. Problems may occur if you export a large database.

--quick,-q

This option is useful when exporting large tables, forcing mysqldump to obtain records directly from a server query instead of having all the records cached in memory.

--routines,-r

Export stored procedures and custom functions.

--single-transaction

This option submits a BEGIN SQL statement before the data is exported, and the begin does not block any applications and guarantees the consistency state of the database at the time of export. It applies only to transaction tables, such as InnoDB and BDB.

This option and the--lock-tables option are mutually exclusive, because lock tables will cause any pending transactions to be implicitly committed.

To export a large table, you should use the--quick option in combination.

--triggers

The trigger is also exported. This option is enabled by default, and it is disabled with--skip-triggers.

For additional parameter details please refer to the manual, I usually use the following SQL to back up the MyISAM table:

/USR/LOCAL/MYSQL/BIN/MYSQLDUMP-UYEJR-PYEJR \

--default-character-set=utf8--opt--extended-insert=false \

--triggers-r--hex-blob-x db_name > Db_name.sql

Use the following SQL to back up the Innodb table:

/USR/LOCAL/MYSQL/BIN/MYSQLDUMP-UYEJR-PYEJR \

--default-character-set=utf8--opt--extended-insert=false \

--triggers-r--hex-blob--single-transaction db_name > Db_name.sql