Reconfiguring a running mysql instance:

mysql> set global binlog_format=ROW;
mysql> set global binlog_row_image=FULL;

note: binlog_format is a session-based property. You will need to shutdown all active connections to fully convert to row-based replication.

GTID support

Maxwell contains support for GTID-based replication. Enable it with the --gtid_mode configuration param.

Here's how you might configure your mysql server for GTID mode:

$ vi my.cnf

[mysqld]
server_id=1
log-bin=master
binlog_format=row
gtid-mode=ON
log-slave-updates=ON
enforce-gtid-consistency=true

When in GTID-mode, Maxwell will transparently pick up a new replication position after a master change. Note that you will still have to re-point maxwell to the new master (or use a floating VIP)

RDS

To run Maxwell against RDS, (either Aurora or Mysql) you will need to do the following:

  • set binlog_format to "ROW". Do this in the "parameter groups" section. For a Mysql-RDS instance this parameter will be in a "DB Parameter Group", for Aurora it will be in a "DB Cluster Parameter Group".
  • setup RDS binlog retention as described here. The tl;dr is to execute call mysql.rds_set_configuration('binlog retention hours', 24) on the server.

Replicating and storing schema from different servers

Maxwell uses MySQL for 3 different functions:

  1. A host to store the captured schema in (--host).
  2. A host to replicate binlogs from (--replication_host).
  3. A host to capture the schema from (--schema_host).

Often, all three hosts are the same. host and replication_host should be different if maxwell is chained off a replica. schema_host should only be used when using the maxscale replication proxy.

Multiple Maxwells

Maxwell can operate with multiple instances running against a single master, in different configurations. This can be useful if you wish to have producers running in different configurations, for example producing different groups of tables to different topics. Each instance of Maxwell must be configured with a unique client_id, in order to store unique binlog positions.

With MySQL 5.5 and below, each replicator (be it mysql, maxwell, whatever) must also be configured with a unique replica_server_id. This is a 32-bit integer that corresponds to mysql's server_id parameter. The value you configure should be unique across all mysql and maxwell instances.

--init_position

This is a dangerous option that you really shouldn't use unless you know what you're doing. It allows you to "rewind" history and go back to a certain point in the binlog. This can work, but you should be aware that Maxwell must have already "visited" that binlog position; simply specifying an arbitrary position in the binlog will lead to Maxwell crashing.

Running with limited permissions

If the user you're running maxwell as can't view part of the database because of limited permissions, Maxwell may be unable to capture information on part of the schem a and the replication stream can break with "Can't find table: XXX" errors. In this case you can enable the ignore_missing_schema flag and configure a filter that will exclude any databases/tables you don't have permission to view.