first draft of db partitioning

awx/main/migrations/0124_event_partitions.py

@@ -0,0 +1,63 @@
+# Generated by Django 2.2.8 on 2020-02-21 16:31
+
+from django.db import migrations, models, connection
+
+
+def migrate_event_data(apps, schema_editor):
+    # see: https://github.com/ansible/awx/issues/9039
+    #
+    # the goal of this function is to:
+    # - [ ] create a parent partition table, main_jobevent_parent
+    # - [ ] .. with a single partition
+    # - [ ] .. that includes all existing job events
+    #
+    # the new main_jobevent_parent table should have a new
+    # denormalized column, job_created, this is used as a
+    # basis for partitioning job event rows
+    #
+    # The initial partion will be a unique case. After
+    # the migration is completed, awx should create
+    # new partitions on an hourly basis, as needed.
+    # All events for a given job should be placed in
+    # a partition based on the job's _created time_.
+
+    # Only partitioning main_jobevent on first pass
+    #
+    #for tblname in (
+    #    'main_jobevent', 'main_inventoryupdateevent',
+    #    'main_projectupdateevent', 'main_adhoccommandevent',
+    #    'main_systemjobevent'
+    #):
+    for tblname in ('main_jobevent',):
+        with connection.cursor() as cursor:
+            # hacky creation of parent table for partition
+            cursor.execute(
+                f'CREATE TABLE {tblname}_parent '
+                f'(LIKE {tblname}, job_created TIMESTAMP  WITH TIME ZONE NOT NULL) '
+                f'PARTITION BY RANGE(job_created);'
+            )
+
+            # .. as well as initial partition containing all existing events
+            cursor.execute(
+                f'CREATE TABLE {tblname}_part0 '
+                f'PARTITION OF {tblname}_parent '
+                f'FOR VALUES FROM (\'2000-01-01 00:00:00.000000+00\') to (\'2021-02-01 00:00:00.000000+00\');'
+            )
+
+            # copy over all job events into partitioned table
+            cursor.execute(
+                f'INSERT INTO {tblname}_parent '
+                f'SELECT {tblname}.*, main_unifiedjob.created '
+                f'FROM {tblname} '
+                f'INNER JOIN main_unifiedjob ON {tblname}.job_id = main_unifiedjob.id;'
+            )
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0123_drop_hg_support'),
+    ]
+
+    operations = [
+        migrations.RunPython(migrate_event_data),
+    ]