Mayra Cabrera authored 5 years ago and Evan Read committed 5 years ago

Indicate it's the author's responsibility to prepare the merge request
for a database review

Mayra Cabrera authored 5 years ago and Evan Read committed 5 years ago

Currently, the DB migrations guide says that "you must" use non-blocking
operations (such as CREATE INDEX CONCURRENTLY), always.

But this does not make sense in cases of empty tables and leads to
splitting the work to multiple non-atomic
(with disable_ddl_transaction!) DB migrations.

To follow KISS principle, to have fewer DB migrations steps,
to have them atomic when it's possible and simplify deployment
and troubleshooting, the following exceptions were added
to the doc:

- index creation,
- index dropping,
- defining an FK,
- adding a column with DEFAULT,

Mayra Cabrera authored 5 years ago and Achilleas Pipinellis committed 5 years ago

- Add a new guideline regarding the file location of background
migrations
- Add a new section about execution timing guidelines for all different
kinds of migrations

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65126.

Came up in the database office hours call on 2019-07-25.

Toon Claes authored 5 years ago and Nick Thomas committed 5 years ago

See https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/6069