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Description

This error indicates an attempt to create a MariaDB scheduled event with a name that is already in use within the database. It typically occurs when a `CREATE EVENT` statement specifies an event identifier that conflicts with an existing event definition.

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Error Message

Event '%s' already exists

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Known Causes

3 known causes

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Attempting Duplicate Event Creation

A `CREATE EVENT` statement was executed using an event name that is already defined in the database, preventing the new event from being added.

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Repeated Script Execution

Deployment or setup scripts that create events might have been run multiple times without checks for existing events, leading to re-attempts at creating already present events.

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Database Migration or Restoration

During a database migration, restoration, or synchronization process, event definitions might be re-applied to a target database that already contains events with identical names.

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Solutions

3 solutions available

1. Drop and Recreate the Event easy

Remove the existing event and then create it again with the same definition.

1

Identify the exact name of the event that is causing the error. This is usually provided in the error message itself (e.g., 'my_scheduled_task').

2

Connect to your MariaDB server using a client like the `mysql` command-line tool or a GUI tool.

mysql -u your_user -p your_database

3

Execute the `DROP EVENT` statement to remove the existing event.

DROP EVENT IF EXISTS event_name;

4

Re-execute the `CREATE EVENT` statement that you were originally trying to run.

CREATE EVENT event_name
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 1 HOUR
DO
  -- Your SQL statements here;

2. Check for Existing Events Before Creation medium

Query the information schema to see if the event already exists before attempting to create it.

1

Connect to your MariaDB server.

mysql -u your_user -p your_database

2

Before executing your `CREATE EVENT` statement, run a query to check if an event with the same name already exists in the `mysql.event` table.

SELECT EVENT_NAME FROM mysql.event WHERE EVENT_NAME = 'event_name';

3

If the query returns a row, the event already exists. You can then choose to either drop it (as in Solution 1) or modify your application logic to avoid redundant creation attempts.

4

Alternatively, you can incorporate this check into a stored procedure or script that handles event creation, ensuring it only proceeds if the event doesn't exist.

DELIMITER //
CREATE PROCEDURE create_my_event_if_not_exists() 
BEGIN 
  IF NOT EXISTS (SELECT EVENT_NAME FROM mysql.event WHERE EVENT_NAME = 'event_name') THEN
    CREATE EVENT event_name
    ON SCHEDULE EVERY 1 DAY
    STARTS CURRENT_TIMESTAMP + INTERVAL 1 HOUR
    DO
      -- Your SQL statements here;
  END IF;
END //
DELIMITER ;

CALL create_my_event_if_not_exists();

3. Review Application Logic for Event Creation advanced

Examine the application code responsible for creating events to prevent duplicate creation attempts.

1

Identify the part of your application code (e.g., scripts, deployment processes, administrative tools) that executes the `CREATE EVENT` statement.

2

Analyze the logic to understand under what conditions the `CREATE EVENT` statement is being called. Is it being called multiple times during application startup, deployment, or configuration?

3

Implement checks within your application logic to ensure the `CREATE EVENT` statement is executed only once. This could involve using flags, checking the `mysql.event` table (as in Solution 2), or ensuring that the creation process is idempotent.

4

Consider using a configuration management tool or a dedicated migration system that manages database schema and object creation to handle event creation in a controlled and repeatable manner.

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Related Errors

5 related errors

MariaDB Error 1537: Event Already Exists