https://sentry.gitlab.net/gitlab/gitlabcom/issues/2735911/?referrer=gitlab_plugin ``` PG::ForeignKeyViolation: ERROR: insert or update on table "merge_request_metrics" violates foreign key constraint "fk_rails_e6d7c24d1b" DETAIL: Key (merge_request_id)=(109395321) is not present in table "merge_requests". activerecord (6.1.3.2) lib/active_record/connection_adapters/postgresql_adapter.rb:672:in `exec_params' activerecord (6.1.3.2) lib/active_record/transactions.rb:354:in `block in with_transaction_returning_status' activerecord (6.1.3.2) lib/active_record/connection_adapters/abstract/database_statements.rb:318:in `transaction' gitlab/database/load_balancing/connection_proxy.rb:116:in `block in write_using_load_balancer' connection.send(name, *args, &block) gitlab/database/load_balancing/load_balancer.rb:101:in `block in read_write' yield connection ... (245 additional frame(s) were not displayed) ActiveRecord::InvalidForeignKey: PG::ForeignKeyViolation: ERROR: insert or update on table "merge_request_metrics" violates foreign key constraint "fk_rails_e6d7c24d1b" DETAIL: Key (merge_request_id)=(109395321) is not present in table "merge_requests". ``` ## Reproduction Steps 1. Fork `gitlab-org/gitlab` to personal group. 1. Edit any file in the fork. 1. Create merge request targeting `gitlab-org/gitlab:master`. 1. Create MR. 1. Error is triggered.