r3032@asus: jeremy | 2005-11-12 23:16:52 -0800

Ticket 428 - stale connections
 r3040@asus:  jeremy | 2005-11-13 00:22:29 -0800
 When AbstractAdapter#log rescues an exception, attempt to detect and reconnect to an inactive database connection.  Connection adapter must respond to the active? and reconnect! instance methods.  Initial support for PostgreSQL.  References #428.


git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3000 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* When AbstractAdapter#log rescues an exception, attempt to detect and reconnect to an inactive database connection.  Connection adapter must respond to the active? and reconnect! instance methods.  Initial support for PostgreSQL.  [Jeremy Kemper]
+
 * Much faster Oracle column reflection.  #2848 [Michael Schoen <schoenm@earthlink.net>]
 
 * Base.reset_sequence_name analogous to reset_table_name (mostly useful for testing).  Base.define_attr_method allows nil values.  [Jeremy Kemper]

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -47,25 +47,24 @@ module ActiveRecord
 
       protected  
         def log(sql, name)
-          begin
-            if block_given?
-              if @logger and @logger.level <= Logger::INFO
-                result = nil
-                seconds = Benchmark.realtime { result = yield }
-                @runtime += seconds
-                log_info(sql, name, seconds)
-                result
-              else
-                yield
-              end
+          if block_given?
+            if @logger and @logger.level <= Logger::INFO
+              result = nil
+              seconds = Benchmark.realtime { result = yield }
+              @runtime += seconds
+              log_info(sql, name, seconds)
+              result
             else
-              log_info(sql, name, 0)
-              nil
+              yield
             end
-          rescue Exception => e
-            log_info("#{e.message}: #{sql}", name, 0)
-            raise ActiveRecord::StatementInvalid, "#{e.message}: #{sql}"
+          else
+            log_info(sql, name, 0)
+            nil
           end
+        rescue Exception => e
+          log_info("#{e.message}: #{sql}", name, 0)
+          reconnect_if_inactive!
+          raise ActiveRecord::StatementInvalid, "#{e.message}: #{sql}"
         end
 
         def log_info(sql, name, runtime)
@@ -96,6 +95,16 @@ module ActiveRecord
             "%s  %s" % [message, dump]
           end
         end
+
+      private
+        def reconnect_if_inactive!
+          if respond_to?(:active?) and respond_to?(:reconnect!)
+            reconnect! unless active?
+            raise ActiveRecord::ConnectionFailed unless active?
+          else
+            @logger.warn "#{adapter_name} does not yet support automatic reconnection." if @logger
+          end
+        end
     end
   end
 end

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -52,6 +52,24 @@ module ActiveRecord
         'PostgreSQL'
       end
 
+      # Is this connection alive and ready for queries?
+      def active?
+        # TODO: postgres-pr doesn't have PGconn#status.
+        if @connection.respond_to?(:status)
+          @connection.status != PGconn::CONNECTION_BAD
+        else
+          true
+        end
+      end
+
+      # Close then reopen the connection.
+      def reconnect!
+        # TODO: postgres-pr doesn't have PGconn#reset.
+        if @connection.respond_to?(:reset)
+          @connection.reset
+        end
+      end
+
       def native_database_types
         {
           :primary_key => "serial primary key",