Fix index for outdated projects on the project_repository_states table

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180531220618) do
+ActiveRecord::Schema.define(version: 20180605213516) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -2040,8 +2040,8 @@ ActiveRecord::Schema.define(version: 20180531220618) do
 
   add_index "project_repository_states", ["last_repository_verification_failure"], name: "idx_repository_states_on_repository_failure_partial", where: "(last_repository_verification_failure IS NOT NULL)", using: :btree
   add_index "project_repository_states", ["last_wiki_verification_failure"], name: "idx_repository_states_on_wiki_failure_partial", where: "(last_wiki_verification_failure IS NOT NULL)", using: :btree
+  add_index "project_repository_states", ["project_id"], name: "idx_repository_states_outdated_checksums", where: "(((repository_verification_checksum IS NULL) AND (last_repository_verification_failure IS NULL)) OR ((wiki_verification_checksum IS NULL) AND (last_wiki_verification_failure IS NULL)))", using: :btree
   add_index "project_repository_states", ["project_id"], name: "index_project_repository_states_on_project_id", unique: true, using: :btree
-  add_index "project_repository_states", ["repository_verification_checksum", "wiki_verification_checksum"], name: "idx_repository_states_on_checksums_partial", where: "((repository_verification_checksum IS NULL) OR (wiki_verification_checksum IS NULL))", using: :btree
 
   create_table "project_statistics", force: :cascade do |t|
     t.integer "project_id", null: false

ee/db/post_migrate/20180605213516_fix_partial_index_to_project_repository_states_checksum_columns.rb

+class FixPartialIndexToProjectRepositoryStatesChecksumColumns < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  OLD_INDEX_NAME = 'idx_repository_states_on_checksums_partial'
+  NEW_INDEX_NAME = 'idx_repository_states_outdated_checksums'
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index_by_name(:project_repository_states, OLD_INDEX_NAME)
+
+    add_concurrent_index(:project_repository_states,
+      :project_id,
+      name: NEW_INDEX_NAME,
+      where: '(repository_verification_checksum IS NULL AND last_repository_verification_failure is NULL) OR (wiki_verification_checksum IS NULL AND last_wiki_verification_failure IS NULL)'
+    )
+  end
+
+  def down
+    remove_concurrent_index_by_name(:project_repository_states, NEW_INDEX_NAME)
+
+    add_concurrent_index(:project_repository_states,
+      [:repository_verification_checksum, :wiki_verification_checksum],
+      name: OLD_INDEX_NAME,
+      length: Gitlab::Database.mysql? ? 20 : nil,
+      where: 'repository_verification_checksum IS NULL OR wiki_verification_checksum IS NULL'
+    )
+  end
+end