opendev/subunit2sql
Code Issues Proposed changes

Set old_alter_table during large mysql migration

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MySQL uses too much tmpdir space to do its newer ALTER optimizations, so
we revert to the simpler method which creates a new table and locks the
old one during the entire operation.

Change-Id: Ifad26f9e7ee70a8acf0f08d6296b97daf500f30b
This commit is contained in:
Clint Byrum 2015-11-27 06:10:40 -08:00
parent ac54f82a80
commit 57a104ae37
1 changed files with 9 additions and 0 deletions
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9
subunit2sql/migrations/versions/2822a408bdd0_uuid_to_integer_ids.py
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@ -214,6 +214,15 @@ def upgrade():
op.alter_column('runs_new', 'new_id',
new_column_name='id')
else:
# http://dev.mysql.com/doc/refman/5.7/en/innodb-online-ddl-syntax.html
# Ths is a specific workaround for limited tmpdir space in the
# OpenStack infra MySQL server. With old_alter_table=OFF, mysql creates
# temporary files that are very large while building the new table.
# So generally, while the old method is less desirable for concurrency,
# it is safer, and we don't need online DDL since this migration
# uses a _new table anyway.
if migration_context.dialect.name == 'mysql':
op.execute('SET SESSION old_alter_table=ON')
with op.batch_alter_table("attachments_new") as batch_op:
batch_op.drop_column('id')
batch_op.alter_column('new_id', new_column_name='id',