实体框架 6 - 定时查询

Question

我正在使用 Entity Framework 6，它是很棒的数据库拦截器功能，用于记录从应用程序发送到数据库的查询。但是，我正在努力为这些查询计时，我有一个长时间运行的查询，它返回数十万到数百万行，因此它需要大约 6 到 15 秒，具体取决于该查询将返回的数据量。实体框架返回一个 SqlDataReader，因此我无法获得获得结果所需的确切时间。我想知道从发送查询到读取最后一行的完整执行时间。有什么办法可以吗。

Answer 1

这是我通常用于 EF 的记录器。

public class EFLoggerForTesting : IDbCommandInterceptor
{
    static readonly ConcurrentDictionary<DbCommand, DateTime> m_StartTime = new ConcurrentDictionary<DbCommand, DateTime>();

    public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        Log(command, interceptionContext);
    }

    public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        Log(command, interceptionContext);
    }

    public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        Log(command, interceptionContext);
    }

    private static void Log<T>(DbCommand command, DbCommandInterceptionContext<T> interceptionContext)
    {
        DateTime startTime;
        TimeSpan duration;


        if (m_StartTime.TryRemove(command, out startTime))
        {
            duration = DateTime.Now - startTime;
        }
        else
            duration = TimeSpan.Zero;

        var requestId =-1;
        string message;

        var parameters = new StringBuilder();
        foreach (DbParameter param in command.Parameters)
        {
            parameters.AppendLine(param.ParameterName + " " + param.DbType + " = " + param.Value);
        }

        if (interceptionContext.Exception == null)
        {
            message = string.Format("Database call took {0} sec. RequestId {1} \r\nCommand:\r\n{2}", duration.TotalSeconds.ToString("N3"), requestId, parameters.ToString() + command.CommandText);
        }
        else
        {
            message = string.Format("EF Database call failed after {0} sec. RequestId {1} \r\nCommand:\r\n{2}\r\nError:{3} ", duration.TotalSeconds.ToString("N3"), requestId, parameters.ToString() + command.CommandText, interceptionContext.Exception);
        }

        Debug.WriteLine(message);
    }


    public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        OnStart(command);
    }

    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        OnStart(command);
    }

    public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        OnStart(command);
    }
    private static void OnStart(DbCommand command)
    {
        m_StartTime.TryAdd(command, DateTime.Now);
    }
}

不幸的是，该文档不存在，所以我不知道这是否适用于您的场景。

Answer 2

如果您正在使用 Web 应用程序，可以尝试 Glimpse：http://getglimpse.com/。否则，试试 MiniProfiler：http://miniprofiler.com/。

Answer 3

正如@Ricardo Peres 的回答所暗示的，Glimpse 对此有好处。它带有Glimpse.Ado 插件，可用于轻松分析任何DbConnection，这是此处扩展的主类。

Glimpse 中 ADO 的手动集成点是将 DbConnection 包装在 GlimpseDbConnection 中，如以下博客文章所示：http://getglimpse.com/Docs/Manual-ADO-Integration。 EF 等其他提供程序会自动与Glimpse.Ef 包集成。

如果您仍然决定要手动实现此目的，我建议您自己包装 DbConneciton 并使用它代替常规的 DbConnection。这样做可以得到简单的时间安排。

你可以在他们的 github 上看到 Glimpse 是如何做到的：https://github.com/Glimpse/Glimpse/tree/master/source/Glimpse.Ado/AlternateType

或者，始终可以选择在存储库级别或方法级别添加此类日志记录，具体取决于您需要多少日志记录。

Answer 4

你可以试试the example explained here

在本例中，我们在命令开始执行时启动Stopwatch，并在命令完成时停止Stopwatch，这样我们可以识别慢查询并记录它们。

public class SqlMonitorInterceptor : IDbCommandInterceptor
{
    private static readonly ILog logger = LogManager.GetCurrentClassLogger();
    private static readonly int sqlWarningThresholdMs = int.Parse(ConfigurationManager.AppSettings["sqlPerformance_warningThresholdMilliseconds"]);
    private readonly Stopwatch _stopwatch = new Stopwatch();

    public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        CommandExecuting();
    }

    public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        CommandExecuted(command, interceptionContext);
    }

    public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        CommandExecuting();
    }

    public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        CommandExecuted(command, interceptionContext);
    }

    public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        CommandExecuting();
    }

    public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        CommandExecuted(command, interceptionContext);
    }

    private void CommandExecuting() {
        _stopwatch.Restart();
    }

    private void CommandExecuted<TResult>(DbCommand command, DbCommandInterceptionContext<TResult> interceptionContext)
    {
        _stopwatch.Stop();
        LogIfError(command, interceptionContext);
        LogIfTooSlow(command, _stopwatch.Elapsed);
    }

    private void LogIfError<TResult>(DbCommand command, DbCommandInterceptionContext<TResult> interceptionContext)
    {
        if (interceptionContext.Exception != null)
        {
            logger.ErrorFormat("Command {0} failed with exception {1}",
                command.CommandText, interceptionContext.Exception);
        }
    }

    private void LogIfTooSlow(DbCommand command, TimeSpan completionTime)
    {
        if (completionTime.TotalMilliseconds > sqlWarningThresholdMs)
        {
            logger.WarnFormat("Query time ({0}ms) exceeded the threshold of {1}ms. Command: \"{2}\"",
                completionTime.TotalMilliseconds, sqlWarningThresholdMs, command.CommandText);
        }
    }
}

Answer 5

Johnathan 接受的答案的 EF Core 版本，供任何人搜索：

using Microsoft.EntityFrameworkCore.Diagnostics;
using System.Data.Common;

public class EFLogger: DbCommandInterceptor
{
    private static readonly ConcurrentDictionary<Guid, DateTime> _startTimes = new ConcurrentDictionary<Guid, DateTime>();

    public override DbDataReader ReaderExecuted(DbCommand command, CommandExecutedEventData eventData, DbDataReader reader)
    {
        Log(command, eventData);
        return reader;
    }

    public override int NonQueryExecuted(DbCommand command, CommandExecutedEventData eventData, int result)
    {
        Log(command, eventData);
        return result;
    }

    public override object ScalarExecuted(DbCommand command, CommandExecutedEventData eventData, object result)
    {
        Log(command, eventData);
        return result;
    }

    public override void CommandFailed(DbCommand command, CommandErrorEventData eventData)
    {
        Log(command, eventData);
    }

    private static void Log(DbCommand command, CommandEventData eventData)
    {
        TimeSpan? duration = null;
        if (_startTimes.TryRemove(eventData.CommandId, out DateTime startTime))
            duration = DateTime.Now - startTime;

        var parameters = new StringBuilder();
        foreach (DbParameter param in command.Parameters)
        {
            parameters.AppendLine(param.ParameterName + " " + param.DbType + " = " + param.Value);
        }

        string message = $"Database call {(eventData is CommandErrorEventData ? "FAILED" : "succeeded")} in {duration?.TotalMilliseconds ?? -1:N3} ms. CommandId {eventData.CommandId} \r\nCommand:\r\n{parameters}{command.CommandText}";
        Console.WriteLine(message);
    }

    public override InterceptionResult<int> NonQueryExecuting(DbCommand command, CommandEventData eventData, InterceptionResult<int> result)
    {
        OnStart(eventData.CommandId);
        return result;
    }
    public override InterceptionResult<DbDataReader> ReaderExecuting(DbCommand command, CommandEventData eventData, InterceptionResult<DbDataReader> result)
    {
        OnStart(eventData.CommandId);
        return result;
    }

    public override InterceptionResult<object> ScalarExecuting(DbCommand command, CommandEventData eventData, InterceptionResult<object> result)
    {
        OnStart(eventData.CommandId);
        return result;
    }

    private void OnStart(Guid commandId)
    {
        _startTimes.TryAdd(commandId, DateTime.Now);
    }
}

Answer 6

下面是我对原始DatabaseLogFormatter 的简化版本。主要区别在于这个没有过滤，我没有记录实际的 SQL 查询或它的参数（因为我只对查询计时感兴趣）。它会记录打开连接、执行查询以及再次关闭连接的时间。正如@aske-b noticed above 使用DateTime （正如公认的答案那样）不是很准确。

---

public class CustomDatabaseLogFormatter : IDbCommandInterceptor, IDbConnectionInterceptor
{
    private readonly Action<string> _writeAction;
    private readonly Stopwatch _stopwatch = new Stopwatch();

    /// <summary>
    /// Creates a formatter that will log every command from any context and also commands that do not originate from a context.
    /// </summary>
    /// <remarks>
    /// This constructor is not used when a delegate is set on <see cref="Database.Log" />. Instead it can be
    /// used by setting the formatter directly using <see cref="DbInterception.Add" />.
    /// </remarks>
    /// <param name="writeAction">The delegate to which output will be sent.</param>
    public CustomDatabaseLogFormatter(Action<string> writeAction)
    {
        Check.NotNull(writeAction, "writeAction");

        _writeAction = writeAction;
    }

    internal Action<string> WriteAction
    {
        get { return _writeAction; }
    }

    /// <summary>
    /// Writes the given string to the underlying write delegate.
    /// </summary>
    /// <param name="output">The string to write.</param>
    protected virtual void Write(string output)
    {
        _writeAction(output);
    }

    /// <summary>
    /// The stopwatch used to time executions. This stopwatch is started at the end of
    /// <see cref="NonQueryExecuting" />, <see cref="ScalarExecuting" />, and <see cref="ReaderExecuting" />
    /// methods and is stopped at the beginning of the <see cref="NonQueryExecuted" />, <see cref="ScalarExecuted" />,
    /// and <see cref="ReaderExecuted" /> methods. If these methods are overridden and the stopwatch is being used
    /// then the overrides should either call the base method or start/stop the stopwatch themselves.
    /// </summary>
    /// <returns>The stopwatch.</returns>
    protected internal Stopwatch Stopwatch
    {
        get { return _stopwatch; }
    }

    private void RestartStopwatch()
    {
        Stopwatch.Restart();
    }

    private void StopStopwatch()
    {
        Stopwatch.Stop();
    }

    #region IDbCommandInterceptor
    /// <summary>
    /// This method is called before a call to <see cref="DbCommand.ExecuteNonQuery" /> or
    /// one of its async counterparts is made.
    /// Starts the stopwatch returned from <see cref="Stopwatch"/>.
    /// </summary>
    /// <param name="command">The command being executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public virtual void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        RestartStopwatch();
    }

    /// <summary>
    /// This method is called after a call to <see cref="DbCommand.ExecuteNonQuery" /> or
    /// one of its async counterparts is made.
    /// Stops the stopwatch returned from <see cref="Stopwatch"/> and calls <see cref="Executed" />.
    /// </summary>
    /// <param name="command">The command being executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public virtual void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        StopStopwatch();
        Executed(command, interceptionContext);
    }

    /// <summary>
    /// This method is called before a call to <see cref="DbCommand.ExecuteReader(CommandBehavior)" /> or
    /// one of its async counterparts is made.
    /// Starts the stopwatch returned from <see cref="Stopwatch"/>.
    /// </summary>
    /// <param name="command">The command being executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public virtual void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        RestartStopwatch();
    }

    /// <summary>
    /// This method is called after a call to <see cref="DbCommand.ExecuteReader(CommandBehavior)" /> or
    /// one of its async counterparts is made.
    /// Stops the stopwatch returned from <see cref="Stopwatch"/> and calls <see cref="Executed" />.
    /// </summary>
    /// <param name="command">The command being executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public virtual void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        StopStopwatch();
        Executed(command, interceptionContext);
    }

    /// <summary>
    /// This method is called before a call to <see cref="DbCommand.ExecuteScalar" />  or
    /// one of its async counterparts is made.
    /// Starts the stopwatch returned from <see cref="Stopwatch"/>.
    /// </summary>
    /// <param name="command">The command being executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public virtual void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        RestartStopwatch();
    }

    /// <summary>
    /// This method is called after a call to <see cref="DbCommand.ExecuteScalar" />  or
    /// one of its async counterparts is made.
    /// Stops the stopwatch returned from <see cref="Stopwatch"/> and calls
    /// <see cref="Executed" />.
    /// </summary>
    /// <param name="command">The command being executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public virtual void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        StopStopwatch();
        Executed(command, interceptionContext);
    }

    /// <summary>
    /// Called whenever a command has completed executing. Calls <see cref="LogResult" />.
    /// </summary>
    /// <typeparam name="TResult">The type of the operation's results.</typeparam>
    /// <param name="command">The command that was executed.</param>
    /// <param name="interceptionContext">Contextual information associated with the command.</param>
    public virtual void Executed<TResult>(DbCommand command, DbCommandInterceptionContext<TResult> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        LogResult(command, interceptionContext);
    }

    /// <summary>
    /// Called to log the result of executing a command.
    /// </summary>
    /// <typeparam name="TResult">The type of the operation's results.</typeparam>
    /// <param name="command">The command being logged.</param>
    /// <param name="interceptionContext">Contextual information associated with the command.</param>
    public virtual void LogResult<TResult>(DbCommand command, DbCommandInterceptionContext<TResult> interceptionContext)
    {
        Check.NotNull(command, "command");
        Check.NotNull(interceptionContext, "interceptionContext");

        var stopwatch = Stopwatch;

        if (interceptionContext.Exception != null)
        {
            Write(
                String.Format(StringResources.CommandLogFailed, stopwatch.ElapsedMilliseconds, interceptionContext.Exception.Message)
                );
        }
        else if (interceptionContext.TaskStatus.HasFlag(TaskStatus.Canceled))
        {
            Write(String.Format(StringResources.CommandLogCanceled, stopwatch.ElapsedMilliseconds));
        }
        else
        {
            var result = interceptionContext.Result;
            var resultString = (object)result == null
                ? "null"
                : (result is DbDataReader)
                    ? result.GetType().Name
                    : result.ToString();
            Write(String.Format(StringResources.CommandLogComplete, stopwatch.ElapsedMilliseconds, resultString));
        }
    }
    #endregion

    #region IDbConnectionInterceptor
    public void BeginningTransaction(DbConnection connection, BeginTransactionInterceptionContext interceptionContext)
    { }

    public void BeganTransaction(DbConnection connection, BeginTransactionInterceptionContext interceptionContext)
    { }

    public void Closing(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
    { }

    /// <summary>
    /// Called after <see cref="DbConnection.Close" /> is invoked.
    /// </summary>
    /// <param name="connection">The connection that was closed.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public void Closed(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
    {
        Check.NotNull(connection, "connection");
        Check.NotNull(interceptionContext, "interceptionContext");

        if (interceptionContext.Exception != null)
        {
            Write(String.Format(StringResources.ConnectionCloseErrorLog, DateTimeOffset.UtcNow, interceptionContext.Exception.Message));
        }
        else
        {
            Write(String.Format(StringResources.ConnectionClosedLog, DateTimeOffset.UtcNow));
        }
    }

    public void ConnectionStringGetting(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void ConnectionStringGot(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void ConnectionStringSetting(DbConnection connection, DbConnectionPropertyInterceptionContext<string> interceptionContext)
    { }

    public void ConnectionStringSet(DbConnection connection, DbConnectionPropertyInterceptionContext<string> interceptionContext)
    { }

    public void ConnectionTimeoutGetting(DbConnection connection, DbConnectionInterceptionContext<int> interceptionContext)
    { }

    public void ConnectionTimeoutGot(DbConnection connection, DbConnectionInterceptionContext<int> interceptionContext)
    { }

    public void DatabaseGetting(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void DatabaseGot(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void DataSourceGetting(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void DataSourceGot(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void Disposing(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
    { }

    public void Disposed(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
    { }

    public void EnlistingTransaction(DbConnection connection, EnlistTransactionInterceptionContext interceptionContext)
    { }

    public void EnlistedTransaction(DbConnection connection, EnlistTransactionInterceptionContext interceptionContext)
    { }

    public void Opening(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
    { }

    /// <summary>
    /// Called after <see cref="DbConnection.Open" /> or its async counterpart is invoked.
    /// </summary>
    /// <param name="connection">The connection that was opened.</param>
    /// <param name="interceptionContext">Contextual information associated with the call.</param>
    public void Opened(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
    {
        Check.NotNull(connection, "connection");
        Check.NotNull(interceptionContext, "interceptionContext");

        if (interceptionContext.Exception != null)
        {
            Write(
                interceptionContext.IsAsync
                    ? String.Format(StringResources.ConnectionOpenErrorLogAsync,
                        DateTimeOffset.UtcNow, interceptionContext.Exception.Message)
                    : String.Format(StringResources.ConnectionOpenErrorLog, DateTimeOffset.UtcNow, interceptionContext.Exception.Message));
        }
        else if (interceptionContext.TaskStatus.HasFlag(TaskStatus.Canceled))
        {
            Write(String.Format(StringResources.ConnectionOpenCanceledLog, DateTimeOffset.UtcNow));
        }
        else
        {
            Write(
                interceptionContext.IsAsync
                    ? String.Format(StringResources.ConnectionOpenedLogAsync, DateTimeOffset.UtcNow)
                    : String.Format(StringResources.ConnectionOpenedLog, DateTimeOffset.UtcNow));
        }
    }

    public void ServerVersionGetting(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void ServerVersionGot(DbConnection connection, DbConnectionInterceptionContext<string> interceptionContext)
    { }

    public void StateGetting(DbConnection connection, DbConnectionInterceptionContext<ConnectionState> interceptionContext)
    { }

    public void StateGot(DbConnection connection, DbConnectionInterceptionContext<ConnectionState> interceptionContext)
    { } 
    #endregion
}

---

internal class Check
{
    public static T NotNull<T>(T value, string parameterName)
        where T : class
    {
        if (value == null)
        {
            throw new ArgumentNullException(parameterName);
        }

        return value;
    }
}

---

StringResources.resx:
CommandLogCanceled          Canceled in {0} ms{1}
CommandLogComplete          Completed in {0} ms with result: {1}
CommandLogFailed            Failed in {0} ms with error: {1}
ConnectionClosedLog         Closed connection at {0}
ConnectionCloseErrorLog     Failed to close connection at {0} with error: {1}
ConnectionOpenCanceledLog   Cancelled open connection at {0}
ConnectionOpenedLog         Opened connection at {0}
ConnectionOpenedLogAsync    Opened connection asynchronously at {0}
ConnectionOpenErrorLog      Failed to open connection at {0} with error: {1}
ConnectionOpenErrorLogAsync Failed to open connection asynchronously at {0} with error: {1}

Answer 7

相当简单，但您不能使用 System.Timers.Timer 对象吗？在 EF 代码之前调用 start，在 EF 代码之后调用 end。如果您在那里有异步代码，您可以调用 .Result 并删除等待，以便同步运行代码并为调用计时。除此之外，如果您使用 SQL 探查器并从另一个值中减去一个值（计时器 - 探查器），您将了解 EF 代码执行所需的时间。