1 files changed, 15 insertions, 37 deletions
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 376d1460db..7eaaff8e13 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -11,14 +11,6 @@ module Arel
         @last_column    = nil
         @quoted_tables  = {}
         @quoted_columns = {}
-        @column_cache   = Hash.new { |h,pool|
-          h[pool] = Hash.new { |conn_h,column|
-            conn_h[column] = {}
-          }
-        }
-        @table_exists   = Hash.new { |h,pool|
-          h[pool] = {}
-        }
       end
 
       def accept object
@@ -38,6 +30,17 @@ module Arel
         ].compact.join ' '
       end
 
+      # FIXME: we should probably have a 2-pass visitor for this
+      def build_subselect key, o
+        stmt             = Nodes::SelectStatement.new
+        core             = stmt.cores.first
+        core.froms       = o.relation
+        core.projections = [key]
+        stmt.limit       = o.limit
+        stmt.orders      = o.orders
+        stmt
+      end
+
       def visit_Arel_Nodes_UpdateStatement o
         if o.orders.empty? && o.limit.nil?
           wheres = o.wheres
@@ -52,15 +55,7 @@ key on UpdateManager using UpdateManager#key=
             key = o.relation.primary_key
           end
 
-          wheres = o.wheres
-          stmt             = Nodes::SelectStatement.new
-          core             = stmt.cores.first
-          core.froms       = o.relation
-          core.projections = [key]
-          stmt.limit       = o.limit
-          stmt.orders      = o.orders
-
-          wheres = [Nodes::In.new(key, [stmt])]
+          wheres = [Nodes::In.new(key, [build_subselect(key, o)])]
         end
 
         [
@@ -88,37 +83,20 @@ key on UpdateManager using UpdateManager#key=
       end
 
       def table_exists? name
-        return true if table_exists.key? name
-
-        @connection.tables.each do |table|
-          table_exists[table] = true
-        end
-
-        table_exists.key? name
-      end
-
-      def table_exists
-        @table_exists[@pool]
+        @pool.table_exists? name
       end
 
       def column_for attr
-        name    = attr.name.to_sym
+        name    = attr.name.to_s
         table   = attr.relation.name
 
         return nil unless table_exists? table
 
-        # If we don't have this column cached, get a list of columns and
-        # cache them for this table
-        unless column_cache.key? table
-          columns = @connection.columns(table, "#{table}(#{name}) Columns")
-          column_cache[table] = Hash[columns.map { |c| [c.name.to_sym, c] }]
-        end
-
         column_cache[table][name]
       end
 
       def column_cache
-        @column_cache[@pool]
+        @pool.columns_hash
       end
 
       def visit_Arel_Nodes_Values o