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"""Add ``max_active_runs`` column to ``dag_model`` table

Revision ID: 092435bf5d12
Revises: 97cdd93827b8
Create Date: 2021-09-06 21:29:24.728923

"""
from __future__ import annotations

import sqlalchemy as sa
from alembic import op
from sqlalchemy import text

# revision identifiers, used by Alembic.
revision = '092435bf5d12'
down_revision = '97cdd93827b8'
branch_labels = None
depends_on = None
airflow_version = '2.1.4'


def upgrade():
    """Apply Add ``max_active_runs`` column to ``dag_model`` table"""
    op.add_column('dag', sa.Column('max_active_runs', sa.Integer(), nullable=True))
    with op.batch_alter_table('dag_run', schema=None) as batch_op:
        # Add index to dag_run.dag_id and also add index to dag_run.state where state==running
        batch_op.create_index('idx_dag_run_dag_id', ['dag_id'])
        batch_op.create_index(
            'idx_dag_run_running_dags',
            ["state", "dag_id"],
            postgresql_where=text("state='running'"),
            mssql_where=text("state='running'"),
            sqlite_where=text("state='running'"),
        )


def downgrade():
    """Unapply Add ``max_active_runs`` column to ``dag_model`` table"""
    with op.batch_alter_table('dag') as batch_op:
        batch_op.drop_column('max_active_runs')
    with op.batch_alter_table('dag_run', schema=None) as batch_op:
        # Drop index to dag_run.dag_id and also drop index to dag_run.state where state==running
        batch_op.drop_index('idx_dag_run_dag_id')
        batch_op.drop_index('idx_dag_run_running_dags')
