Alembic revision to deal with changelog index hitting max int size. (#…

…174)

* Alembic revision to deal with changelog index hitting max int size.

* Updated Changelog model to use BigInteger.

* Trying to work out BigInt upgrade.

* Uncommented function.

* Revert sequence to int in downgrade.

* Fixed integer type name. Removed unused BigInteger import in models.py

.gitignore

@@ -103,6 +103,7 @@ ENV/
 # emacs
 *~
 
+local_config.py
 logs
 python/*
 venv/*

alembic/versions/2d2af8a9c996_upgrade_change_log.py

@@ -0,0 +1,55 @@
+"""upgrade_change_log
+
+Revision ID: 2d2af8a9c996
+Revises: 0155d2dff74e
+Create Date: 2023-11-13 14:56:21.410177
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '2d2af8a9c996'
+down_revision = '0155d2dff74e'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+
+
+def upgrade():
+    op.execute('ALTER TABLE change_log ADD COLUMN big_id BIGINT;')
+    op.execute('CREATE FUNCTION set_new_id() RETURNS TRIGGER AS\n'\
+                   '$BODY$\n'\
+                   'BEGIN\n'\
+                   '\t NEW.big_id := NEW.id;\n'\
+                   '\t RETURN NEW;\n'\
+                   'END\n'\
+                   '$BODY$ LANGUAGE PLPGSQL;\n'\
+                   'CREATE TRIGGER set_new_id_trigger BEFORE INSERT OR UPDATE ON {}\n'\
+                   'FOR EACH ROW EXECUTE PROCEDURE set_new_id();\n'.format('change_log'))
+    op.execute('UPDATE change_log SET big_id=id')
+    op.execute('CREATE UNIQUE INDEX IF NOT EXISTS big_id_unique ON change_log(big_id);')
+    op.execute('ALTER TABLE change_log ADD CONSTRAINT big_id_not_null CHECK (big_id IS NOT NULL) NOT VALID;')
+    op.execute('ALTER TABLE change_log VALIDATE CONSTRAINT big_id_not_null;')
+    op.execute('ALTER TABLE change_log DROP CONSTRAINT change_log_pkey, ADD CONSTRAINT change_log_pkey PRIMARY KEY USING INDEX big_id_unique;')
+    op.execute('ALTER SEQUENCE change_log_id_seq OWNED BY change_log.big_id;')
+    op.execute("ALTER TABLE change_log ALTER COLUMN big_id SET DEFAULT nextval('change_log_id_seq');")
+    op.execute("ALTER TABLE change_log RENAME COLUMN id TO old_id;")
+    op.execute("ALTER TABLE change_log RENAME COLUMN big_id TO id;")
+    op.drop_column('change_log', 'old_id')
+    op.execute('ALTER SEQUENCE change_log_id_seq as bigint MAXVALUE 9223372036854775807')
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    op.add_column('change_log', sa.Column('smallid', sa.Integer(), unique=True))
+    op.execute('DELETE FROM change_log WHERE id > 2147483647')
+    op.execute('UPDATE change_log SET smallid=id')
+    op.alter_column('change_log', 'smallid', nullable=False)
+    op.drop_constraint('change_log_pkey', 'change_log', type_='primary')
+    op.create_primary_key("change_log_pkey", "change_log", ["smallid", ])
+    op.alter_column('change_log', 'id', nullable=False, new_column_name='old_id')
+    op.alter_column('change_log', 'smallid', nullable=False, new_column_name='id')
+    op.drop_column('change_log', 'old_id')
+    op.execute('ALTER SEQUENCE change_log_id_seq as integer MAXVALUE 2147483647')
+