Update READ_QUERY regex

  * The READ_QUERY regex would consider reads to be writes if they started with
    spaces or parens. For example, a UNION query might have parens around each
    SELECT - (SELECT ...) UNION (SELECT ...).
  * It will now correctly treat these queries as reads.

1 files changed, 1 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index c1d846f58d..f205d77ddb 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -102,7 +102,7 @@ module ActiveRecord
       end
 
       def self.build_read_query_regexp(*parts) # :nodoc:
-        parts = parts.map { |part| /\A\s*#{part}/i }
+        parts = parts.map { |part| /\A[\(\s]*#{part}/i }
         Regexp.union(*parts)
       end