SpirirHost Support Centre: MySQL Reference Manual p.316

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Table of Contents
1. General Information
2. MySQL Installation
3. Tutorial Introduction
4. Database Administration
5. MySQL Optimisation
6. MySQL Language Reference
7. MySQL Table Types
8. MySQL APIs
9. Extending MySQL

316 MySQL Technical Reference for Version 4.0.3 the master's binary log it has processed. Do not remove or edit the le, unless you really know what you are doing. Even in that case, it is preferred that you use CHANGE MASTER TO command. 4.10.4 Replication Features and Known Problems Here is an explanation of what is supported and what is not: Replication will be done correctly with AUTO_INCREMENT, LAST_INSERT_ID(), and TIMESTAMP values. RAND() in updates does not replicate properly. Use RAND(some_non_rand_expr) if you are replicating updates with RAND(). You can, for example, use UNIX_TIMESTAMP() for the argument to RAND(). You have to use the same character set (--default-character-set) on the master and the slave. If not, you may get duplicate key errors on the slave, because a key that is regarded as unique on the master may not be that in the other character set. In 3.23, LOAD DATA INFILE will be handled properly as long as the le still resides on the master server at the time of update propagation. LOAD LOCAL DATA INFILE will be skipped. In 4.0, this limitation is not present - all forms of LOAD DATA INFILE are properly replicated. Update queries that use user variables are not replication-safe (yet). FLUSH commands are not stored in the binary log and are because of this not replicated to the slaves. This is not normally a problem as FLUSH doesn't change anything. This does however mean that if you update the MySQL privilege tables directly without using the GRANT statement and you replicate the mysql privilege database, you must do a FLUSH PRIVILEGES on your slaves to put the new privileges into eect. Temporary tables starting in 3.23.29 are replicated properly with the exception of the case when you shut down slave server ( not just slave thread), you have some temporary tables open, and they are used in subsequent updates. To deal with this problem shutting down the slave, do SLAVE STOP, check Slave_open_temp_tables variable to see if it is 0, then issue mysqladmin shutdown. If the number is not 0, restart the slave thread with SLAVE START and see if you have better luck next time. There will be a cleaner solution, but it has to wait until version 4.0. In earlier versions temporary tables are not replicated properly - we recommend that you either upgrade, or execute SET SQL_LOG_BIN=0 on your clients before all queries with temp tables. MySQL only supports one master and many slaves. In 4.x, we will add a voting algorithm to automatically change master if something goes wrong with the current master. We will also introduce 'agent' processes to help do load balancing by sending select queries to dierent slaves. Starting in Version 3.23.26, it is safe to connect servers in a circular master-slave relationship with log-slave-updates enabled. Note, however, that many queries will not work right in this kind of setup unless your client code is written to take care of the potential problems that can happen from updates that occur in dierent sequence on dierent servers. This means that you can do a setup like the following:

MySQL Reference Manual

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