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Replication works because events written to the binary log are read from the master and then processed on the slave. The events are recorded within the binary log in different formats according to the type of event. The different replication formats used correspond to the binary logging format used when the events were recorded in the master's binary log. The correlation between binary logging formats and the terms used during replication are:
Replication capabilities in MySQL originally were based on propagation of SQL statements from master to slave. This is called statement-based replication (often abbreviated as SBR), which corresponds to the standard statement-based binary logging format. In older versions of MySQL (5.1.4 and earlier), binary logging and replication used this format exclusively.
Row-based binary logging logs changes in individual table rows. When used with MySQL replication, this is known as row-based replication (often abbreviated as RBR). In row-based replication, the master writes events to the binary log that indicate how individual table rows are changed.
The server can change the binary logging format in real time according to the type of event using mixed-format logging.
When the mixed format is in effect, statement-based logging is used by default, but automatically switches to row-based logging in particular cases as described later. Replication using the mixed format is often referred to as mixed-based replication or mixed-format replication. For more information, see Section 5.2.4.3, “Mixed Binary Logging Format”.
In MySQL 5.5, statement-based format is the default.
MySQL Cluster.
The default binary logging format in all MySQL Cluster NDB
6.1, 6.2, 6.3, and later 6.x releases is
ROW
. MySQL Cluster Replication always uses
row-based replication, and the
NDBCLUSTER
storage engine is
incompatible with statement-based replication. Using
NDBCLUSTER
sets row-based logging
format automatically.
See MySQL Cluster Replication — Assumptions and General Requirements, for more information.
When using MIXED
format, the binary logging
format is determined in part by the storage engine being used and
the statement being executed. For more information on mixed-format
logging and the rules governing the support of different logging
formats, see Section 5.2.4.3, “Mixed Binary Logging Format”.
The logging format in a running MySQL server is controlled by
setting the binlog_format
server
system variable. This variable can be set with session or global
scope. The rules governing when and how the new setting takes
effect are the same as for other MySQL server system variables
— setting the variable for the current session lasts only
until the end of that session, and the change is not visible to
other sessions; setting the variable globally requires a restart
of the server in order to take effect. For more information, see
Section 12.4.4, “SET
Syntax”.
You must have the SUPER
privilege
to set either the global or session
binlog_format
value.
The statement-based and row-based replication formats have different issues and limitations. For a comparison of their relative advantages and disadvantages, see Section 16.1.2.1, “Comparison of Statement-Based and Row-Based Replication”.
With statement-based replication, you may encounter issues with replicating stored routines or triggers. You can avoid these issues by using row-based replication instead. For more information, see Section 18.6, “Binary Logging of Stored Programs”.
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