Prevent extra `SET time zone` in `configure_connection` (#28413)

`SET time zone 'value'` is an alias for `SET timezone TO 'value'`.

https://www.postgresql.org/docs/current/static/sql-set.html

So if `variables["timezone"]` is specified, it is enough to
`SET timezone` once.

1 files changed, 7 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/postgresql/connection_test.rb b/activerecord/test/cases/adapters/postgresql/connection_test.rb
index 24875c6678..2bb217a8b1 100644
--- a/activerecord/test/cases/adapters/postgresql/connection_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/connection_test.rb
@@ -220,6 +220,13 @@ module ActiveRecord
       end
     end
 
+    def test_set_session_timezone
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(orig_connection.deep_merge(variables: { timezone: "America/New_York" }))
+        assert_equal "America/New_York", ActiveRecord::Base.connection.query_value("SHOW TIME ZONE")
+      end
+    end
+
     def test_get_and_release_advisory_lock
       lock_id = 5295901941911233559
       list_advisory_locks = <<-SQL