diff --git a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
index f6be9e9..0828d59 100644
--- a/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
+++ b/core/lib/Drupal/Core/Database/Driver/pgsql/Schema.php
@@ -727,7 +727,7 @@ public function changeField($table, $field, $field_new, $spec, $new_keys = array
     // the typecast does not work for conversions to bytea.
     // @see http://www.postgresql.org/docs/current/static/datatype-binary.html
     $table_information = $this->queryTableInformation($table);
-    $is_bytea = in_array($field, $table_information->blob_fields, TRUE);
+    $is_bytea = !empty($table_information->blob_fields[$field]);
     if ($spec['pgsql_type'] != 'bytea') {
       if ($is_bytea) {
         $this->connection->query('ALTER TABLE {' . $table . '} ALTER "' . $field . '" TYPE ' . $field_def . ' USING convert_from("' . $field . '"' . ", 'UTF8')");
diff --git a/core/modules/system/src/Tests/Database/SchemaTest.php b/core/modules/system/src/Tests/Database/SchemaTest.php
index e6aea74..5f60bf6 100644
--- a/core/modules/system/src/Tests/Database/SchemaTest.php
+++ b/core/modules/system/src/Tests/Database/SchemaTest.php
@@ -725,6 +725,7 @@ protected function assertFieldChange($old_spec, $new_spec, $test_data = NULL) {
         ->condition('serial_column', $id)
         ->execute()
         ->fetchField();
+      $this->pass($old_spec['type'] .' to '. $new_spec['type']);
       $this->assertIdentical($field_value, $test_data);
     }