diff --git a/changelogs/unreleased/add-index-for-auto_canceled_by_id-mysql.yml b/changelogs/unreleased/add-index-for-auto_canceled_by_id-mysql.yml
new file mode 100644
index 0000000000000000000000000000000000000000..eac78e9ee1fcb2164231d986fb9fca4fd089ab02
--- /dev/null
+++ b/changelogs/unreleased/add-index-for-auto_canceled_by_id-mysql.yml
@@ -0,0 +1,4 @@
+---
+title: Add indices for auto_canceled_by_id for ci_pipelines and ci_builds on PostgreSQL
+merge_request: 11034
+author:
diff --git a/db/migrate/20170502135553_create_index_ci_pipelines_auto_canceled_by_id.rb b/db/migrate/20170502135553_create_index_ci_pipelines_auto_canceled_by_id.rb
new file mode 100644
index 0000000000000000000000000000000000000000..b64d7e0e3f6effe73578d0cd124ff77c202501d0
--- /dev/null
+++ b/db/migrate/20170502135553_create_index_ci_pipelines_auto_canceled_by_id.rb
@@ -0,0 +1,21 @@
+class CreateIndexCiPipelinesAutoCanceledById < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    # MySQL would already have the index
+    unless index_exists?(:ci_pipelines, :auto_canceled_by_id)
+      add_concurrent_index(:ci_pipelines, :auto_canceled_by_id)
+    end
+  end
+
+  def down
+    # We cannot remove index for MySQL because it's needed for foreign key
+    if Gitlab::Database.postgresql?
+      remove_concurrent_index(:ci_pipelines, :auto_canceled_by_id)
+    end
+  end
+end
diff --git a/db/migrate/20170502140503_create_index_ci_builds_auto_canceled_by_id.rb b/db/migrate/20170502140503_create_index_ci_builds_auto_canceled_by_id.rb
new file mode 100644
index 0000000000000000000000000000000000000000..0a8d2c8ff61ea4f564df06f334c923febc4d1aa9
--- /dev/null
+++ b/db/migrate/20170502140503_create_index_ci_builds_auto_canceled_by_id.rb
@@ -0,0 +1,21 @@
+class CreateIndexCiBuildsAutoCanceledById < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    # MySQL would already have the index
+    unless index_exists?(:ci_builds, :auto_canceled_by_id)
+      add_concurrent_index(:ci_builds, :auto_canceled_by_id)
+    end
+  end
+
+  def down
+    # We cannot remove index for MySQL because it's needed for foreign key
+    if Gitlab::Database.postgresql?
+      remove_concurrent_index(:ci_builds, :auto_canceled_by_id)
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index b938657a186557b164103d34ecc6dc8407b4da68..d411a137b7059fd123e5f1a04cabb4ef9afc530b 100644
--- a/db/schema.rb
+++ b/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: 20170426181740) do
+ActiveRecord::Schema.define(version: 20170502140503) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -232,6 +232,7 @@ ActiveRecord::Schema.define(version: 20170426181740) do
     t.integer "auto_canceled_by_id"
   end
 
+  add_index "ci_builds", ["auto_canceled_by_id"], name: "index_ci_builds_on_auto_canceled_by_id", using: :btree
   add_index "ci_builds", ["commit_id", "stage_idx", "created_at"], name: "index_ci_builds_on_commit_id_and_stage_idx_and_created_at", using: :btree
   add_index "ci_builds", ["commit_id", "status", "type"], name: "index_ci_builds_on_commit_id_and_status_and_type", using: :btree
   add_index "ci_builds", ["commit_id", "type", "name", "ref"], name: "index_ci_builds_on_commit_id_and_type_and_name_and_ref", using: :btree
@@ -263,6 +264,7 @@ ActiveRecord::Schema.define(version: 20170426181740) do
     t.integer "auto_canceled_by_id"
   end
 
+  add_index "ci_pipelines", ["auto_canceled_by_id"], name: "index_ci_pipelines_on_auto_canceled_by_id", using: :btree
   add_index "ci_pipelines", ["project_id", "ref", "status"], name: "index_ci_pipelines_on_project_id_and_ref_and_status", using: :btree
   add_index "ci_pipelines", ["project_id", "sha"], name: "index_ci_pipelines_on_project_id_and_sha", using: :btree
   add_index "ci_pipelines", ["project_id"], name: "index_ci_pipelines_on_project_id", using: :btree