diff options
| -rw-r--r-- | nova/db/sqlalchemy/migrate_repo/versions/144_add_node_to_migrations.py | 52 |
1 files changed, 30 insertions, 22 deletions
diff --git a/nova/db/sqlalchemy/migrate_repo/versions/144_add_node_to_migrations.py b/nova/db/sqlalchemy/migrate_repo/versions/144_add_node_to_migrations.py index 97b0f7bb0..692f9599b 100644 --- a/nova/db/sqlalchemy/migrate_repo/versions/144_add_node_to_migrations.py +++ b/nova/db/sqlalchemy/migrate_repo/versions/144_add_node_to_migrations.py @@ -1,4 +1,4 @@ -# Copyright 2012 OpenSmigrations.ck LLC. +# Copyright 2012 Openstack LLC. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain @@ -16,6 +16,29 @@ from sqlalchemy import and_, Index, String, Column, MetaData, Table from sqlalchemy.sql.expression import select, update +def _drop_index(engine, table, idx_name): + """Drop index from DB and remove index from SQLAlchemy table metadata. + + idx.drop() in SQLAlchemy will issue a DROP INDEX statement to the DB but + WILL NOT update the table metadata to remove the `Index` object. + + This can cause subsequent drop column calls on a related column to fail + because `drop_column` will see an `Index` object that isn't there, thus + issuing an erroneous second DROP INDEX call. + + The solution is to update the table metadata to reflect the now dropped + column. + """ + for idx in getattr(table, 'indexes'): + if idx.name == idx_name: + break + else: + raise Exception("Index '%s' not found!" % idx_name) + + idx.drop(engine) + table.indexes.remove(idx) + + def upgrade(migrate_engine): meta = MetaData() meta.bind = migrate_engine @@ -52,15 +75,14 @@ def downgrade(migrate_engine): migrations = Table('migrations', meta, autoload=True) - # drop new columns: - source_node = Column('source_node', String(length=255)) - migrations.drop_column(source_node) + # drop new index: + _drop_index(migrate_engine, migrations, + 'migrations_by_host_nodes_and_status_idx') - dest_node = Column('dest_node', String(length=255)) - migrations.drop_column(dest_node) + # drop new columns: + migrations.drop_column('source_node') - # drop new index: - _drop_new_index(migrations, migrate_engine) + migrations.drop_column('dest_node') # re-add old index: i = _old_index(migrations) @@ -110,20 +132,6 @@ def _add_new_index(migrations, migrate_engine): i.create(migrate_engine) -def _drop_new_index(migrations, migrate_engine): - if migrate_engine.name == "mysql": - sql = ("drop index migrations_by_host_nodes_and_status_idx on " - "migrations") - migrate_engine.execute(sql) - - else: - i = Index('migrations_by_host_nodes_and_status_idx', - migrations.c.deleted, migrations.c.source_compute, - migrations.c.dest_compute, migrations.c.source_node, - migrations.c.dest_node, migrations.c.status) - i.drop(migrate_engine) - - def _old_index(migrations): i = Index('migrations_by_host_and_status_idx', migrations.c.deleted, migrations.c.source_compute, migrations.c.dest_compute, |