188.8.131.52 Replication of Invoked Features
Replication of invoked features such as user-defined functions (UDFs) and stored programs (stored procedures and functions, triggers, and events) provides the following characteristics:
The effects of the feature are always replicated.
The following statements are replicated using statement-based replication:
However, the effects of features created, modified, or dropped using these statements are replicated using row-based replication.Note
Attempting to replicate invoked features using statement-based replication produces the warning Statement is not safe to log in statement format. For example, trying to replicate a UDF with statement-based replication generates this warning because it currently cannot be determined by the MySQL server whether the UDF is deterministic. If you are absolutely certain that the invoked feature's effects are deterministic, you can safely disregard such warnings.
The status of the event is set to
SLAVESIDE_DISABLEDon the replica regardless of the state specified (this does not apply to
The source on which the event was created is identified on the replica by its server ID. The
mysql.eventstore this information. See Section 24.8, “The INFORMATION_SCHEMA EVENTS Table”, and Section 184.108.40.206, “SHOW EVENTS Statement”, for more information.
The feature implementation resides on the replica in a renewable state so that if the source fails, the replica can be used as the source without loss of event processing.
To determine whether there are any scheduled events on a MySQL server that were created on a different server (that was acting as a replication source server), query the
INFORMATION_SCHEMA.EVENTS table in a manner similar to what is shown here:
SELECT EVENT_SCHEMA, EVENT_NAME FROM INFORMATION_SCHEMA.EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED';
Alternatively, you can use the
SHOW EVENTS statement, like this:
SHOW EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED';
When promoting a replica having such events to a replication source server, you must enable each event using
ALTER EVENT , where
event_name is the name of the event.
If more than one source was involved in creating events on this replica, and you wish to identify events that were created only on a given source having the server ID
source_id, modify the previous query on the
EVENTS table to include the
ORIGINATOR column, as shown here:
SELECT EVENT_SCHEMA, EVENT_NAME, ORIGINATOR FROM INFORMATION_SCHEMA.EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED' AND ORIGINATOR = 'source_id'
You can employ
ORIGINATOR with the
SHOW EVENTS statement in a similar fashion:
SHOW EVENTS WHERE STATUS = 'SLAVESIDE_DISABLED' AND ORIGINATOR = 'source_id'
Before enabling events that were replicated from the source, you should disable the MySQL Event Scheduler on the replica (using a statement such as
SET GLOBAL event_scheduler = OFF;), run any necessary
ALTER EVENT statements, restart the server, then re-enable the Event Scheduler on the replica afterward (using a statement such as
SET GLOBAL event_scheduler = ON;)-
If you later demote the new source back to being a replica, you must disable manually all events enabled by the
ALTER EVENT statements. You can do this by storing in a separate table the event names from the
SELECT statement shown previously, or using
ALTER EVENT statements to rename the events with a common prefix such as
replicated_ to identify them.
If you rename the events, then when demoting this server back to being a replica, you can identify the events by querying the
EVENTS table, as shown here:
SELECT CONCAT(EVENT_SCHEMA, '.', EVENT_NAME) AS 'Db.Event' FROM INFORMATION_SCHEMA.EVENTS WHERE INSTR(EVENT_NAME, 'replicated_') = 1;