Bug #87412 The behaviour of the triggers after "INSERT ... ON DUPLICATE KEY UPDATE"
Submitted: 14 Aug 2017 13:25 Modified: 24 Oct 2018 18:34
Reporter: Sinisa Milivojevic Email Updates:
Status: Closed Impact on me:
None 
Category:MySQL Server: Documentation Severity:S3 (Non-critical)
Version:5.6, 5.7 OS:Any
Assigned to: CPU Architecture:Any

[14 Aug 2017 13:25] Sinisa Milivojevic 
Description:
There is an inconsistency in the behaviour of the triggers as mentioned in the title, that needs to be documented.

How to repeat:
See bug #87371

Suggested fix:
Expand documentation on triggers.
[24 Oct 2018 18:34] Paul Dubois 
Posted by developer:
 
The underlying bug (Bug#87371) has been fixed, so there's no longer an exceptional behavior to document for that.

Regarding behavior of ON DUPLICATE KEY UPDATE and triggers, that is already documented at
https://dev.mysql.com/doc/refman/8.0/en/create-trigger.html:

The trigger_event does not represent a literal type of SQL statement that activates the trigger so much as it represents a type of table operation. For example, an INSERT trigger activates not only for INSERT statements but also LOAD DATA statements because both statements insert rows into a table.

A potentially confusing example of this is the INSERT INTO ... ON DUPLICATE KEY UPDATE ... syntax: a BEFORE INSERT trigger activates for every row, followed by either an AFTER INSERT trigger or both the BEFORE UPDATE and AFTER UPDATE triggers, depending on whether there was a duplicate key for the row.