MySQL Bugs: #74401: testUpgrade -n Upgrade_Api_Before_NR1 T2 fails due to concurrent createDropEvent

Bug #74401	testUpgrade -n Upgrade_Api_Before_NR1 T2 fails due to concurrent createDropEvent
Submitted:	15 Oct 2014 12:28	Modified:	27 Nov 2014 9:34
Reporter:	Mauritz Sundell	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Tests: Cluster	Severity:	S3 (Non-critical)
Version:	7.2.18	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
The test Upgrade_Api_Before_NR1 has two parallel steps in it's post upgrade phase.

Both calls createDropEvent that go through a list of tables and first creates an event for it followed by dropping it.

Occasionally they call it for the same table at the same time, and one of them get
Failed to drop event: 4710 : Event not found

Since the function always to a dropEvent without checking the result right before it does createEvent, createEvent will unlikely fail due to this concurrency.

How to repeat:
Run test testUpgrade -n Upgrade_Api_Before_NR1 T2.
Failures have been recorded in autotest runs at ndbmaster

Suggested fix:
To fix, either
* disable one of the calls to createDropEvent, or
* serialize calls to create/drop event for a table within the test program,
and probably also dropEvent call in createEvent can me removed or modified.

Thank you for your bug report. This issue has been committed to our source repository of that product and will be incorporated into the next release.

Fixed in NDB 7.1.34, 7.2.19, 7.3.8, and 7.4.3. 

This affects testing only, so no changelog entry is needed.

Closed.

If necessary, you can access the source repository and build the latest available version, including the bug fix. More information about accessing the source trees is available at

    http://dev.mysql.com/doc/en/installing-source.html