1842924 - Deleting performance_datum row fails when it's associated to performance_datum_replicate's

Status: RESOLVED FIXED

(Tree Management :: Perfherder, defect, P2)

Description

[Greg Mierzwinski [:sparky]]

I was looking at the performance datum max age for the try branch and found that it was over the 42 days currently being used: https://sql.telemetry.mozilla.org/queries/92654/source

I found bug 1681473 where we hit an issue with deleting data on the multicommitdatum table, and it seems similar to what we might be hitting here. I added the following test and found that deletion was definitely failing (not sure if we can find this in any prod logs?):

def test_deleting_performance_data_cascades_to_perf_datum_replicate(test_perf_data):
    perf_datum = test_perf_data[0]
    PerformanceDatumReplicate.objects.create(performance_datum=perf_datum, value=0.0)

    assert PerformanceDatumReplicate.objects.count() == 1

    try:
        cursor = connection.cursor()
        cursor.execute(
            '''
            DELETE FROM `performance_datum`
            WHERE id = %s
            ''',
            [perf_datum.id],
        )
    except IntegrityError:
        pytest.fail()
    finally:
        cursor.close()

    assert PerformanceDatumReplicate.objects.count() == 0

Error:

E       django.db.utils.IntegrityError: (1451, 'Cannot delete or update a parent row: a foreign key constraint fails (`test_treeherder`.`performance_datum_replicate`, CONSTRAINT `performance_datum_re_performance_datum_id_fe2ed518_fk_performan` FOREIGN KEY (`performance_datum_id`) REFERENCES `performance_datum)')

/usr/local/lib/python3.9/site-packages/MySQLdb/connections.py:259: IntegrityError

I get the same error when I try to delete a performance_datum row from a database viewer/editor.

I've followed the patch in bug 1681473 to make a similar migration for the table so that we can delete the performance_datum rows again. I'll post a PR shortly.

Comment 1

[Greg Mierzwinski [:sparky]]

PR for it here: https://github.com/mozilla/treeherder/pull/7744

Comment 2

[Greg Mierzwinski [:sparky]]

PR landed, and has been deployed to prod. The data is now being deleted, with June 2nd being the oldest date found for the data on try (previously May 18th): https://sql.telemetry.mozilla.org/queries/92654/source