Add primary key to mrcc_diff_files table
What does this MR do?
Related to #270093 (closed)
Add a primary key to the merge_request_context_commit_diff_files table. The suggested PK was (merge_request_context_commit_id, relative_order). Since merge_request_context_commit_id currently allows null values, we have to delete any offending rows, and then ensure we have no duplicates before the primary key is added.
We have an index to support the delete of null records: https://explain.depesz.com/s/ddnd
Tried the delete of duplicates initially with a subquery but it was quite slow, the current approach seems work well: https://explain.depesz.com/s/gHLl
Does this MR meet the acceptance criteria?
Conformity
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Changelog entry -
Documentation (if required) -
Code review guidelines -
Merge request performance guidelines -
Style guides -
Database guides -
Separation of EE specific content
Availability and Testing
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Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process. -
Tested in all supported browsers -
Informed Infrastructure department of a default or new setting change, if applicable per definition of done
Security
If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:
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Label as security and @ mention @gitlab-com/gl-security/appsec -
The MR includes necessary changes to maintain consistency between UI, API, email, or other methods -
Security reports checked/validated by a reviewer from the AppSec team