17.3.4 Replicating Different Databases to Different Slaves

There may be situations where you have a single master and want to replicate different databases to different slaves. For example, you may want to distribute different sales data to different departments to help spread the load during data analysis. A sample of this layout is shown in Figure 17.2, “Using Replication to Replicate Databases to Separate Replication Slaves”.

Figure 17.2 Using Replication to Replicate Databases to Separate Replication Slaves

Using replication to replicate databases to separate replication slaves

You can achieve this separation by configuring the master and slaves as normal, and then limiting the binary log statements that each slave processes by using the --replicate-wild-do-table configuration option on each slave.

Important

You should not use --replicate-do-db for this purpose when using statement-based replication, since statement-based replication causes this option's affects to vary according to the database that is currently selected. This applies to mixed-format replication as well, since this enables some updates to be replicated using the statement-based format.

However, it should be safe to use --replicate-do-db for this purpose if you are using row-based replication only, since in this case the currently selected database has no effect on the option's operation.

For example, to support the separation as shown in Figure 17.2, “Using Replication to Replicate Databases to Separate Replication Slaves”, you should configure each replication slave as follows, before executing START SLAVE:

Each slave in this configuration receives the entire binary log from the master, but executes only those events from the binary log that apply to the databases and tables included by the --replicate-wild-do-table option in effect on that slave.

If you have data that must be synchronized to the slaves before replication starts, you have a number of choices: