The Ultimate Guide to High Availability with MariaDB

Using CONNECT - Condition Pushdown

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The ODBC, JDBC, MYSQL, TBL and WMI table types use engine condition pushdown in order to restrict the number of rows returned by the RDBS source or the WMI component.

MariaDB starting with 10.0.4

Since MariaDB 10.0.4, the CONDITION_PUSHDOWN argument is no longer accepted. However, it is not needed because CONNECT now uses condition pushdown unconditionally.

MariaDB until 10.0.4

If the engine condition pushdown is OFF, it is necessary to set it ON with the optimizer_switch setting, for instance by:

set optimizer_switch='engine_condition_pushdown=on';

Or launching mysqld with this parameter set to ON, for instance:

mysqld --console --engine_condition_pushdown=on

Note 1: specifying --console is important to have some error messages from CONNECT printed because MariaDB does not always retrieve them.

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