diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index e30b481fe1..ba3dd49e7e 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -83,7 +83,7 @@ HEADER
 
           # first dump primary key column
           if @connection.respond_to?(:pk_and_sequence_for)
-            pk, pk_seq = @connection.pk_and_sequence_for(table)
+            pk = @connection.pk_and_sequence_for(table).first
           elsif @connection.respond_to?(:primary_key)
             pk = @connection.primary_key(table)
           end