Using MiniProfiler's database profiling with NHibernate - nhibernate

Question

What's the simplest way to use MiniProfiler's database profiling with NHibernate? In order for the profiler to work, I need to wrap the DbConnection that NHibernate uses in a ProfiledDbConnection.
I'm not too familiar with the internals of NHibernate, so I don't know where all the extensibility points are. (I noticed that an NHibernate ISession has a Connection property, but it is read-only.)

Answer 1

[UPDATE] Please see the following links for a version of that uses RealProxy to proxy the SqlCommand - batching is now supported
blog http://blog.fearofaflatplanet.me.uk/mvcminiprofiler-and-nhibernate-take-2
gist https://gist.github.com/1110153
I've left the original answer unaltered as it was accepted. [/UPDATE]
I've managed to partially get this to work by implementing a Profiled Client Driver (example for Sql Server 2008 below) - this works for simple examples, however I haven't yet found a solution for NH batching (which attempts to cast the command back to SqlCommand)
public class ProfiledSql2008ClientDriver : Sql2008ClientDriver
{
public override IDbCommand CreateCommand()
{
return new ProfiledDbCommand(
base.CreateCommand() as DbCommand,
null,
MiniProfiler.Current);
}
public override IDbConnection CreateConnection()
{
return ProfiledDbConnection.Get(
base.CreateConnection() as DbConnection,
MiniProfiler.Current);
}
}

Answer 2

I extended Roberts answer above to work with NHibernate batching. There is a lot of code here so it can possibly be shortened, some of it based on the nHibernate source for the client driver.
<property name="connection.driver_class">YoureOnTime.Data.ProfiledSqlClientDriver, YoureOnTime.Common</property>
public class ProfiledSqlClientDriver : DriverBase, IEmbeddedBatcherFactoryProvider
{
public override IDbConnection CreateConnection()
{
return new ProfiledSqlDbConnection(
new SqlConnection(),
MiniProfiler.Current);
}
public override IDbCommand CreateCommand()
{
return new ProfiledSqlDbCommand(
new SqlCommand(),
null,
MiniProfiler.Current);
}
public override bool UseNamedPrefixInSql
{
get { return true; }
}
public override bool UseNamedPrefixInParameter
{
get { return true; }
}
public override string NamedPrefix
{
get { return "#"; }
}
public override bool SupportsMultipleOpenReaders
{
get { return false; }
}
public static void SetParameterSizes(IDataParameterCollection parameters, SqlType[] parameterTypes)
{
for (int i = 0; i < parameters.Count; i++)
{
SetVariableLengthParameterSize((IDbDataParameter)parameters[i], parameterTypes[i]);
}
}
private const int MaxAnsiStringSize = 8000;
private const int MaxBinarySize = MaxAnsiStringSize;
private const int MaxStringSize = MaxAnsiStringSize / 2;
private const int MaxBinaryBlobSize = int.MaxValue;
private const int MaxStringClobSize = MaxBinaryBlobSize / 2;
private const byte MaxPrecision = 28;
private const byte MaxScale = 5;
private const byte MaxDateTime2 = 8;
private const byte MaxDateTimeOffset = 10;
private static void SetDefaultParameterSize(IDbDataParameter dbParam, SqlType sqlType)
{
switch (dbParam.DbType)
{
case DbType.AnsiString:
case DbType.AnsiStringFixedLength:
dbParam.Size = MaxAnsiStringSize;
break;
case DbType.Binary:
if (sqlType is BinaryBlobSqlType)
{
dbParam.Size = MaxBinaryBlobSize;
}
else
{
dbParam.Size = MaxBinarySize;
}
break;
case DbType.Decimal:
dbParam.Precision = MaxPrecision;
dbParam.Scale = MaxScale;
break;
case DbType.String:
case DbType.StringFixedLength:
dbParam.Size = IsText(dbParam, sqlType) ? MaxStringClobSize : MaxStringSize;
break;
case DbType.DateTime2:
dbParam.Size = MaxDateTime2;
break;
case DbType.DateTimeOffset:
dbParam.Size = MaxDateTimeOffset;
break;
}
}
private static bool IsText(IDbDataParameter dbParam, SqlType sqlType)
{
return (sqlType is StringClobSqlType) || (sqlType.LengthDefined && sqlType.Length > MsSql2000Dialect.MaxSizeForLengthLimitedStrings &&
(DbType.String == dbParam.DbType || DbType.StringFixedLength == dbParam.DbType));
}
private static void SetVariableLengthParameterSize(IDbDataParameter dbParam, SqlType sqlType)
{
SetDefaultParameterSize(dbParam, sqlType);
// Override the defaults using data from SqlType.
if (sqlType.LengthDefined && !IsText(dbParam, sqlType))
{
dbParam.Size = sqlType.Length;
}
if (sqlType.PrecisionDefined)
{
dbParam.Precision = sqlType.Precision;
dbParam.Scale = sqlType.Scale;
}
}
public override IDbCommand GenerateCommand(CommandType type, SqlString sqlString, SqlType[] parameterTypes)
{
IDbCommand command = base.GenerateCommand(type, sqlString, parameterTypes);
//if (IsPrepareSqlEnabled)
{
SetParameterSizes(command.Parameters, parameterTypes);
}
return command;
}
public override bool SupportsMultipleQueries
{
get { return true; }
}
#region IEmbeddedBatcherFactoryProvider Members
System.Type IEmbeddedBatcherFactoryProvider.BatcherFactoryClass
{
get { return typeof(ProfiledSqlClientBatchingBatcherFactory); }
}
#endregion
}
public class ProfiledSqlClientBatchingBatcher : AbstractBatcher
{
private int batchSize;
private int totalExpectedRowsAffected;
private SqlClientSqlCommandSet currentBatch;
private StringBuilder currentBatchCommandsLog;
private readonly int defaultTimeout;
public ProfiledSqlClientBatchingBatcher(ConnectionManager connectionManager, IInterceptor interceptor)
: base(connectionManager, interceptor)
{
batchSize = Factory.Settings.AdoBatchSize;
defaultTimeout = PropertiesHelper.GetInt32(NHibernate.Cfg.Environment.CommandTimeout, NHibernate.Cfg.Environment.Properties, -1);
currentBatch = CreateConfiguredBatch();
//we always create this, because we need to deal with a scenario in which
//the user change the logging configuration at runtime. Trying to put this
//behind an if(log.IsDebugEnabled) will cause a null reference exception
//at that point.
currentBatchCommandsLog = new StringBuilder().AppendLine("Batch commands:");
}
public override int BatchSize
{
get { return batchSize; }
set { batchSize = value; }
}
protected override int CountOfStatementsInCurrentBatch
{
get { return currentBatch.CountOfCommands; }
}
public override void AddToBatch(IExpectation expectation)
{
totalExpectedRowsAffected += expectation.ExpectedRowCount;
IDbCommand batchUpdate = CurrentCommand;
string lineWithParameters = null;
var sqlStatementLogger = Factory.Settings.SqlStatementLogger;
if (sqlStatementLogger.IsDebugEnabled || log.IsDebugEnabled)
{
lineWithParameters = sqlStatementLogger.GetCommandLineWithParameters(batchUpdate);
var formatStyle = sqlStatementLogger.DetermineActualStyle(FormatStyle.Basic);
lineWithParameters = formatStyle.Formatter.Format(lineWithParameters);
currentBatchCommandsLog.Append("command ")
.Append(currentBatch.CountOfCommands)
.Append(":")
.AppendLine(lineWithParameters);
}
if (log.IsDebugEnabled)
{
log.Debug("Adding to batch:" + lineWithParameters);
}
currentBatch.Append(((ProfiledSqlDbCommand)batchUpdate).Command);
if (currentBatch.CountOfCommands >= batchSize)
{
ExecuteBatchWithTiming(batchUpdate);
}
}
protected void ProfiledPrepare(IDbCommand cmd)
{
try
{
IDbConnection sessionConnection = ConnectionManager.GetConnection();
if (cmd.Connection != null)
{
// make sure the commands connection is the same as the Sessions connection
// these can be different when the session is disconnected and then reconnected
if (cmd.Connection != sessionConnection)
{
cmd.Connection = sessionConnection;
}
}
else
{
cmd.Connection = (sessionConnection as ProfiledSqlDbConnection).Connection;
}
ProfiledSqlDbTransaction trans = (ProfiledSqlDbTransaction)typeof(NHibernate.Transaction.AdoTransaction).InvokeMember("trans", System.Reflection.BindingFlags.GetField | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance, null, ConnectionManager.Transaction, null);
if (trans != null)
cmd.Transaction = trans.Transaction;
Factory.ConnectionProvider.Driver.PrepareCommand(cmd);
}
catch (InvalidOperationException ioe)
{
throw new ADOException("While preparing " + cmd.CommandText + " an error occurred", ioe);
}
}
protected override void DoExecuteBatch(IDbCommand ps)
{
log.DebugFormat("Executing batch");
CheckReaders();
ProfiledPrepare(currentBatch.BatchCommand);
if (Factory.Settings.SqlStatementLogger.IsDebugEnabled)
{
Factory.Settings.SqlStatementLogger.LogBatchCommand(currentBatchCommandsLog.ToString());
currentBatchCommandsLog = new StringBuilder().AppendLine("Batch commands:");
}
int rowsAffected;
try
{
rowsAffected = currentBatch.ExecuteNonQuery();
}
catch (DbException e)
{
throw ADOExceptionHelper.Convert(Factory.SQLExceptionConverter, e, "could not execute batch command.");
}
Expectations.VerifyOutcomeBatched(totalExpectedRowsAffected, rowsAffected);
currentBatch.Dispose();
totalExpectedRowsAffected = 0;
currentBatch = CreateConfiguredBatch();
}
private SqlClientSqlCommandSet CreateConfiguredBatch()
{
var result = new SqlClientSqlCommandSet();
if (defaultTimeout > 0)
{
try
{
result.CommandTimeout = defaultTimeout;
}
catch (Exception e)
{
if (log.IsWarnEnabled)
{
log.Warn(e.ToString());
}
}
}
return result;
}
}
public class ProfiledSqlClientBatchingBatcherFactory : IBatcherFactory
{
public virtual IBatcher CreateBatcher(ConnectionManager connectionManager, IInterceptor interceptor)
{
return new ProfiledSqlClientBatchingBatcher(connectionManager, interceptor);
}
}
public class ProfiledSqlDbCommand : ProfiledDbCommand
{
public ProfiledSqlDbCommand(SqlCommand cmd, SqlConnection conn, MiniProfiler profiler)
: base(cmd, conn, profiler)
{
Command = cmd;
}
public SqlCommand Command { get; set; }
private DbTransaction _trans;
protected override DbTransaction DbTransaction
{
get { return _trans; }
set
{
this._trans = value;
ProfiledSqlDbTransaction awesomeTran = value as ProfiledSqlDbTransaction;
Command.Transaction = awesomeTran == null ? (SqlTransaction)value : awesomeTran.Transaction;
}
}
}
public class ProfiledSqlDbConnection : ProfiledDbConnection
{
public ProfiledSqlDbConnection(SqlConnection connection, MiniProfiler profiler)
: base(connection, profiler)
{
Connection = connection;
}
public SqlConnection Connection { get; set; }
protected override DbTransaction BeginDbTransaction(System.Data.IsolationLevel isolationLevel)
{
return new ProfiledSqlDbTransaction(Connection.BeginTransaction(isolationLevel), this);
}
}
public class ProfiledSqlDbTransaction : ProfiledDbTransaction
{
public ProfiledSqlDbTransaction(SqlTransaction transaction, ProfiledDbConnection connection)
: base(transaction, connection)
{
Transaction = transaction;
}
public SqlTransaction Transaction { get; set; }
}

Answer 3

Try implementing NHibernate.Connection.IConnectionProvider (you could just inherit DriverConnectionProvider), in GetConnection() wrap the IDbConnection as you need.
Plug your connection provider using the Environment.ConnectionProvider key in your config properties.

Answer 4

If anyone is interested I have done an integration using a custom Log4net appender instead. This way I feel safe that I don't mess with the Connection object.
The rough outline is something along these lines: NHibernate emits the sqlstrings as debug statements and the appender configured in log4net.xml calls Start and Dispose on the MiniProfiler.