启用连接池时，dataadapter.fill命令在高负载下随机返回0行

Question

We have been having issues with ADO.NET commands in ASP.NET applications, we have norrowed it down to this...

No errors are returned but instead the dataadapter.fill command just returns 0 rows.

This only happens some of the time, the vast majority of the time, the query executes normally. We know SQL server didn't return an error (using sql profiler), and the query should have returned a result (re-running the dataadapter.fill does return some rows and the rows have always existed in the database) This seems to happen only when we have ado.net connection pooling turned on and when the server is under heavy load.

We are using SqlClient connection/command objects and connecting to a SQL Server database (we've seen this behaviour with SQL 2005 and SQL 2008 so far)

Answer 1

Does the select statement return multiple resultsets? If yes then you might want to use:

using(DbDataAdapter dataAdapter = _providerFactory.CreateDataAdapter())
{
  dataAdapter.TableMappings.AddRange(tableMappings);
  dataAdapter.SelectCommand = selectCommand;

  // This is crucial for HasChanges() to return the correct value
  dataAdapter.AcceptChangesDuringFill = false;

  MyTypedDataSet dataSet = new MyTypedDataSet();
  dataSet.EnforceConstraints = false;
  dataAdapter.Fill(dataSet);
  bool hasData = dataSet.HasChanges();
  return hasData;
}