Remove unneeded index packages_debian_*_architectures.distribution_id

See https://gitlab.com/gitlab-org/gitlab/-/merge_requests/51732#note_491491814

changelogs/unreleased/debian_architectures_unneeded_index.yml

+---
+title: Remove unneeded index on packages_debian_{project,group}_architectures.distribution_id
+merge_request: 59615
+author: Mathieu Parent
+type: removed

db/migrate/20210419090412_remove_debian_group_architectures_distribution_id_index.rb

+# frozen_string_literal: true
+
+class RemoveDebianGroupArchitecturesDistributionIdIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  INDEX_NAME = 'idx_pkgs_deb_grp_architectures_on_distribution_id'
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index :packages_debian_group_architectures, :distribution_id, name: INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index :packages_debian_group_architectures, :distribution_id, name: INDEX_NAME
+  end
+end

db/migrate/20210419090542_remove_debian_project_architectures_distribution_id_index.rb

+# frozen_string_literal: true
+
+class RemoveDebianProjectArchitecturesDistributionIdIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  INDEX_NAME = 'idx_pkgs_deb_proj_architectures_on_distribution_id'
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index :packages_debian_project_architectures, :distribution_id, name: INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index :packages_debian_project_architectures, :distribution_id, name: INDEX_NAME
+  end
+end

db/schema_migrations/20210419090412

+da9c3d764a5750a40e0f6edd2e713efd77620ba3e684e48d47c7f855e47b2984
\ No newline at end of file

db/schema_migrations/20210419090542

+7a7b0eaa67851aa9300e4750fd05c6d2d0b49ca7077099a0208a89c74ac03a2c
\ No newline at end of file

db/structure.sql

@@ -21785,10 +21785,6 @@ CREATE INDEX idx_packages_debian_project_component_files_on_architecture_id ON p
 
 CREATE INDEX idx_packages_packages_on_project_id_name_version_package_type ON packages_packages USING btree (project_id, name, version, package_type);
 
-CREATE INDEX idx_pkgs_deb_grp_architectures_on_distribution_id ON packages_debian_group_architectures USING btree (distribution_id);
-
-CREATE INDEX idx_pkgs_deb_proj_architectures_on_distribution_id ON packages_debian_project_architectures USING btree (distribution_id);
-
 CREATE UNIQUE INDEX idx_pkgs_dep_links_on_pkg_id_dependency_id_dependency_type ON packages_dependency_links USING btree (package_id, dependency_id, dependency_type);
 
 CREATE INDEX idx_proj_feat_usg_on_jira_dvcs_cloud_last_sync_at_and_proj_id ON project_feature_usages USING btree (jira_dvcs_cloud_last_sync_at, project_id) WHERE (jira_dvcs_cloud_last_sync_at IS NOT NULL);