1 files changed, 51 insertions, 41 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/schema_cache.rb b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
index b14b37ce89..aad1f9a7ef 100644
--- a/activerecord/lib/active_record/connection_adapters/schema_cache.rb
+++ b/activerecord/lib/active_record/connection_adapters/schema_cache.rb
@@ -1,71 +1,81 @@
 module ActiveRecord
   module ConnectionAdapters
     class SchemaCache
-      attr_reader :columns, :columns_hash, :primary_keys, :tables
-      attr_reader :column_defaults
-      attr_reader :connection
+      attr_reader :columns, :columns_hash, :primary_keys, :tables, :version
+      attr_accessor :connection
 
       def initialize(conn)
         @connection = conn
-        @tables              = {}
 
-        @columns     = Hash.new do |h, table_name|
-          h[table_name] =
-            # Fetch a list of columns
-            conn.columns(table_name, "#{table_name} Columns").tap do |cs|
-              # set primary key information
-              cs.each do |column|
-                column.primary = column.name == primary_keys[table_name]
-              end
-            end
-        end
-
-        @columns_hash = Hash.new do |h, table_name|
-          h[table_name] = Hash[columns[table_name].map { |col|
-            [col.name, col]
-          }]
-        end
-
-        @column_defaults = Hash.new do |h, table_name|
-          h[table_name] = Hash[columns[table_name].map { |col|
-            [col.name, col.default]
-          }]
-        end
-
-        @primary_keys = Hash.new do |h, table_name|
-          h[table_name] = table_exists?(table_name) ?
-                          conn.primary_key(table_name) : 'id'
-        end
+        @columns      = {}
+        @columns_hash = {}
+        @primary_keys = {}
+        @tables       = {}
+        prepare_default_proc
       end
 
       # A cached lookup for table existence.
       def table_exists?(name)
         return @tables[name] if @tables.key? name
 
-        connection.tables.each { |table| @tables[table] = true }
-        @tables[name] = connection.table_exists?(name) if !@tables.key?(name)
+        @tables[name] = connection.table_exists?(name)
+      end
 
-        @tables[name]
+      # Add internal cache for table with +table_name+.
+      def add(table_name)
+        if table_exists?(table_name)
+          @primary_keys[table_name]
+          @columns[table_name]
+          @columns_hash[table_name]
+        end
       end
 
-      # Clears out internal caches:
-      #
-      #   * columns
-      #   * columns_hash
-      #   * tables
+      # Clears out internal caches
       def clear!
         @columns.clear
         @columns_hash.clear
-        @column_defaults.clear
+        @primary_keys.clear
         @tables.clear
+        @version = nil
       end
 
       # Clear out internal caches for table with +table_name+.
       def clear_table_cache!(table_name)
         @columns.delete table_name
         @columns_hash.delete table_name
-        @column_defaults.delete table_name
         @primary_keys.delete table_name
+        @tables.delete table_name
+      end
+
+      def marshal_dump
+        # if we get current version during initialization, it happens stack over flow.
+        @version = ActiveRecord::Migrator.current_version
+        [@version] + [:@columns, :@columns_hash, :@primary_keys, :@tables].map do |val|
+          self.instance_variable_get(val).inject({}) { |h, v| h[v[0]] = v[1]; h }
+        end
+      end
+
+      def marshal_load(array)
+        @version, @columns, @columns_hash, @primary_keys, @tables = array
+        prepare_default_proc
+      end
+
+      private
+
+      def prepare_default_proc
+        @columns.default_proc = Proc.new do |h, table_name|
+          h[table_name] = connection.columns(table_name)
+        end
+
+        @columns_hash.default_proc = Proc.new do |h, table_name|
+          h[table_name] = Hash[columns[table_name].map { |col|
+            [col.name, col]
+          }]
+        end
+
+        @primary_keys.default_proc = Proc.new do |h, table_name|
+          h[table_name] = table_exists?(table_name) ? connection.primary_key(table_name) : nil
+        end
       end
     end
   end