Merge pull request #42993 from sambostock/use-precision-in-updated-at-upsert

Use correct precision when touching `updated_at` column in upsert

activerecord/CHANGELOG.md

@@ -1,3 +1,15 @@
+*   Use full precision for `updated_at` in `insert_all`/`upsert_all`
+
+    `CURRENT_TIMESTAMP` provides differing precision depending on the database,
+    and not all databases support explicitly specifying additional precision.
+
+    Instead, we delegate to the new `connection.high_precision_current_timestamp`
+    for the SQL to produce a high precision timestamp on the current database.
+
+    Fixes #42992
+
+    *Sam Bostock*
+
 * Add ssl support for postgresql database tasks
 
     Add `PGSSLMODE`, `PGSSLCERT`, `PGSSLKEY` and `PGSSLROOTCERT` to pg_env from database config

activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb

@@ -441,6 +441,19 @@ module ActiveRecord
         end
       end
 
+      # This is a safe default, even if not high precision on all databases
+      HIGH_PRECISION_CURRENT_TIMESTAMP = Arel.sql("CURRENT_TIMESTAMP").freeze # :nodoc:
+      private_constant :HIGH_PRECISION_CURRENT_TIMESTAMP
+
+      # Returns an Arel SQL literal for the CURRENT_TIMESTAMP for usage with
+      # arbitrary precision date/time columns.
+      #
+      # Adapters supporting datetime with precision should override this to
+      # provide as much precision as is available.
+      def high_precision_current_timestamp
+        HIGH_PRECISION_CURRENT_TIMESTAMP
+      end
+
       private
         def execute_batch(statements, name = nil)
           statements.each do |statement|

activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb

@@ -76,6 +76,15 @@ module ActiveRecord
         end
         alias :exec_update :exec_delete
 
+        # https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_current-timestamp
+        # https://dev.mysql.com/doc/refman/5.7/en/date-and-time-type-syntax.html
+        HIGH_PRECISION_CURRENT_TIMESTAMP = Arel.sql("CURRENT_TIMESTAMP(6)").freeze # :nodoc:
+        private_constant :HIGH_PRECISION_CURRENT_TIMESTAMP
+
+        def high_precision_current_timestamp
+          HIGH_PRECISION_CURRENT_TIMESTAMP
+        end
+
         private
           def raw_execute(sql, name, async: false)
             # make sure we carry over any changes to ActiveRecord.default_timezone that have been

activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb

@@ -123,6 +123,14 @@ module ActiveRecord
           execute("ROLLBACK", "TRANSACTION")
         end
 
+        # From https://www.postgresql.org/docs/current/functions-datetime.html#FUNCTIONS-DATETIME-CURRENT
+        HIGH_PRECISION_CURRENT_TIMESTAMP = Arel.sql("CURRENT_TIMESTAMP").freeze # :nodoc:
+        private_constant :HIGH_PRECISION_CURRENT_TIMESTAMP
+
+        def high_precision_current_timestamp
+          HIGH_PRECISION_CURRENT_TIMESTAMP
+        end
+
         private
           def execute_batch(statements, name = nil)
             execute(combine_multi_statements(statements))

activerecord/lib/active_record/connection_adapters/sqlite3/database_statements.rb

@@ -97,6 +97,15 @@ module ActiveRecord
           reset_read_uncommitted
         end
 
+        # https://stackoverflow.com/questions/17574784
+        # https://www.sqlite.org/lang_datefunc.html
+        HIGH_PRECISION_CURRENT_TIMESTAMP = Arel.sql("STRFTIME('%Y-%m-%d %H:%M:%f', 'NOW')").freeze # :nodoc:
+        private_constant :HIGH_PRECISION_CURRENT_TIMESTAMP
+
+        def high_precision_current_timestamp
+          HIGH_PRECISION_CURRENT_TIMESTAMP
+        end
+
         private
           def reset_read_uncommitted
             read_uncommitted = Thread.current.thread_variable_get("read_uncommitted")

activerecord/lib/active_record/insert_all.rb

@@ -198,7 +198,7 @@ module ActiveRecord
         def touch_model_timestamps_unless(&block)
           model.timestamp_attributes_for_update_in_model.filter_map do |column_name|
             if touch_timestamp_attribute?(column_name)
-              "#{column_name}=(CASE WHEN (#{updatable_columns.map(&block).join(" AND ")}) THEN #{model.quoted_table_name}.#{column_name} ELSE CURRENT_TIMESTAMP END),"
+              "#{column_name}=(CASE WHEN (#{updatable_columns.map(&block).join(" AND ")}) THEN #{model.quoted_table_name}.#{column_name} ELSE #{connection.high_precision_current_timestamp} END),"
             end
           end.join
         end

activerecord/test/cases/insert_all_test.rb

@@ -364,6 +364,15 @@ class InsertAllTest < ActiveRecord::TestCase
     assert_equal Time.now.year, Book.find(101).updated_on.year
   end
 
+  def test_upsert_all_respects_updated_at_precision_when_touched_implicitly
+    skip unless supports_insert_on_duplicate_update? && supports_datetime_with_precision?
+
+    Book.insert_all [{ id: 101, name: "Out of the Silent Planet", published_on: Date.new(1938, 4, 1), updated_at: 5.years.ago, updated_on: 5.years.ago }]
+    Book.upsert_all [{ id: 101, name: "Out of the Silent Planet", published_on: Date.new(1938, 4, 8) }]
+
+    assert_not_predicate Book.find(101).updated_at.usec, :zero?, "updated_at should have sub-second precision"
+  end
+
   def test_upsert_all_uses_given_updated_at_over_implicit_updated_at
     skip unless supports_insert_on_duplicate_update?
 

activerecord/test/schema/schema.rb

@@ -119,8 +119,13 @@ ActiveRecord::Schema.define do
     t.index :isbn, where: "published_on IS NOT NULL", unique: true
     t.index "(lower(external_id))", unique: true if supports_expression_index?
 
-    t.datetime :created_at
-    t.datetime :updated_at
+    if supports_datetime_with_precision?
+      t.datetime :created_at, precision: 6
+      t.datetime :updated_at, precision: 6
+    else
+      t.datetime :created_at
+      t.datetime :updated_at
+    end
     t.date :updated_on
   end