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12.6.2.3 LOAD TABLE tbl_name FROM MASTER Syntax »
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12.6.2.2. LOAD DATA FROM MASTER Syntax

LOAD DATA FROM MASTER

This feature is deprecated and should be avoided. It is subject to removal in a future version of MySQL.

Since the current implementation of LOAD DATA FROM MASTER and LOAD TABLE FROM MASTER is very limited, these statements are deprecated in versions 4.1 of MySQL and above. We will introduce a more advanced technique (called “online backup”) in a future version. That technique will have the additional advantage of working with more storage engines.

For MySQL 5.1 and earlier, the recommended alternative solution to using LOAD DATA FROM MASTER or LOAD TABLE FROM MASTER is using mysqldump or mysqlhotcopy. The latter requires Perl and two Perl modules (DBI and DBD:mysql) and works for MyISAM and ARCHIVE tables only. With mysqldump, you can create SQL dumps on the master and pipe (or copy) these to a mysql client on the slave. This has the advantage of working for all storage engines, but can be quite slow, since it works using SELECT.

This statement takes a snapshot of the master and copies it to the slave. It updates the values of MASTER_LOG_FILE and MASTER_LOG_POS so that the slave starts replicating from the correct position. Any table and database exclusion rules specified with the --replicate-*-do-* and --replicate-*-ignore-* options are honored. --replicate-rewrite-db is not taken into account because a user could use this option to set up a nonunique mapping such as --replicate-rewrite-db="db1->db3" and --replicate-rewrite-db="db2->db3", which would confuse the slave when loading tables from the master.

Use of this statement is subject to the following conditions:

  • It works only for MyISAM tables. Attempting to load a non-MyISAM table results in the following error: 

    ERROR 1189 (08S01): Net error reading from master

  • It acquires a global read lock on the master while taking the snapshot, which prevents updates on the master during the load operation.

If you are loading large tables, you might have to increase the values of net_read_timeout and net_write_timeout on both the master and slave servers. See Section 5.1.4, “Server System Variables”.

Note that LOAD DATA FROM MASTER does not copy any tables from the mysql database. This makes it easy to have different users and privileges on the master and the slave.

To use LOAD DATA FROM MASTER, the replication account that is used to connect to the master must have the RELOAD and SUPER privileges on the master and the SELECT privilege for all master tables you want to load. All master tables for which the user does not have the SELECT privilege are ignored by LOAD DATA FROM MASTER. This is because the master hides them from the user: LOAD DATA FROM MASTER calls SHOW DATABASES to know the master databases to load, but SHOW DATABASES returns only databases for which the user has some privilege. See Section 12.5.5.15, “SHOW DATABASES Syntax”. On the slave side, the user that issues LOAD DATA FROM MASTER must have privileges for dropping and creating the databases and tables that are copied.


User Comments

Posted by [name withheld] on June 18 2004 5:15pm[Delete] [Edit]

A behavior that me off the first time I set up replication using LOAD DATA FROM MASTER is that LOAD DATA FROM MASTER always says "0 rows affected" even if the database(s) have been successfully retrieved/updated.mm

Posted by [name withheld] on February 8 2006 7:16pm[Delete] [Edit]

LOAD DATA FROM MASTER, used as indicated above, does not work on 3.23.x. There is no Super_priv. FYI.

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