MaxScale/Documentation/Filters/BinlogFilter.md

BinlogFilter

This filter was introduced in MariaDB MaxScale 2.3.

Overview

The BinlogFilter filter is capable of filtering and replacing the binlog events sent from BinlogRouter to slave servers.

This filter, once configured with a database or table name, inspects the binlog events being delivered from Binlog Server to connected slave servers. If a match for db/table occurs in binlog events such as TABLE_MAP and QUERY_EVENT, all the following ones are replaced with small (35 bytes) RAND_EVENT events. The replacement continues until a COMMIT, new TABLE_MAP event or QUERY_EVENT is seen.

The result is that the slave server is not getting any real data about DDLs or DMLS related to the configured db/table.

Assuming a simple transaction with an INSERT is being delivered with ROW based replication, the slave server sees:

• GTID (BEGIN)
• RAND_EVENT (instead of TABLE_MAP)
• RAND_EVENT (instead of WRITE_ROWS)
• XID (COMMIT)

This replacement also saves network bandwidth as a 3MB BLOB update is not sent by MaxScale Binlog Server to any slave, just a 35 bytes RAND_EVENT is sent istead.

Note:

• In case of large event transmission, i.e. 33MBytes, all the 3 packets (16 + 16 + 1 MB) that form the large event are replaced by RAND_EVENT
• The packet sequence is always kept during the replacement.
• No configuration is needed in the slave servers.
• The filter can work with both ROW and STATEMENT based replication.

Configuration

The BinlogFilter configuration is very easy, and in its first implementation it has no mandatory parameters.

Optional parameters are:

filter_events

Enables the binlog filtering, default is Off

filter_events=On

skip_db

Specifies the database name to skip. Empty setting, skip_db=, or no setting means that all database names are allowed. The default value is empty value.

skip_db=orders_t1

skip_table

Specifies the table name to skip. Empty setting, skip_table=, or no setting means that all tables names are allowed. The default value is empty value.

skip_db=cat_obj

Example Configuration

Here is an example of BinlogFilter:

All binlog events belonging to database test and table tbl1 are replaced.

[BinlogFilter]
type=filter
module=binlogfilter
filter_events=On
skip_db=test
skip_table=tbl1

[BinlogServer]
type=service
router=binlogrouter
server-id=33,
filters=BinlogFilter