我找到了一种方法来做到这一点,只需保持 SQL 计时,主页步骤仍然正确添加:
var asyncTask = new Task<T>(
profiler =>
{
var currentProfiler = (profiler as MiniProfiler);
// Create a new profiler just for this step, we're only going to use the SQL timings
MiniProfiler newProfiler = null;
if (currentProfiler != null)
{
newProfiler = new MiniProfiler("Async step", currentProfiler.Level);
}
using(var con = /* create new DB connection */)
using(var profiledCon = new ProfiledDbConnection(con, newProfiler))
{
// ### Do long running SQL stuff ###
profiledCon.Query...
}
// If we have a profiler and a current step
if (currentProfiler != null && currentProfiler.Head != null)
{
// Add the SQL timings to the step that's active when the SQL completes
var currentStep = currentProfiler.Head;
foreach (var sqlTiming in newProfiler.GetSqlTimings())
{
currentStep.AddSqlTiming(sqlTiming);
}
}
return result;
}, MiniProfiler.Current);
这会导致长时间运行的查询的 SQL 计时在 SQL 完成时与当前步骤相关联。通常,这是等待异步结果的步骤,但如果 SQL 在我必须等待此结果之前完成,那么这将是更早的步骤。
我用简洁的风格包裹了它QueryAsync<T>
扩展方法(总是缓冲且不支持事务),尽管它可以做很多整理工作。当我有更多时间时,我会考虑添加一个ProfiledTask<T>
或类似的,允许从已完成的任务复制分析结果。
更新 1(适用于 1.9)
根据 Sam 的评论(见下文),他是对的:AddSqlTiming
不是线程安全的。因此,为了解决这个问题,我已将其移至同步延续:
// explicit result class for the first task
class ProfiledResult<T>
{
internal List<SqlTiming> SqlTimings { get; set; }
internal T Result { get; set; }
}
var currentStep = MiniProfiler.Current.Head;
// Create a task that has its own profiler
var asyncTask = new Task<ProfiledResult<T>>(
() =>
{
// Create a new profiler just for this step, we're only going to use the SQL timings
var newProfiler = new MiniProfiler("Async step");
var result = new ProfiledResult<T>();
result.Result = // ### Do long running SQL stuff ###
// Get the SQL timing results
result.SqlTimings = newProfiler.GetSqlTimings();
return result;
});
// When the task finishes continue on the main thread to add the SQL timings
var asyncWaiter = asyncTask.ContinueWith<T>(
t =>
{
// Get the wrapped result and add the timings from SQL to the current step
var completedResult = t.Result;
foreach (var sqlTiming in completedResult.SqlTimings)
{
currentStep.AddSqlTiming(sqlTiming);
}
return completedResult.Result;
}, TaskContinuationOptions.ExecuteSynchronously);
asyncTask.Start();
return asyncWaiter;
这适用于 MvcMiniProfiler 1.9,但不适用于 MiniProfiler 2...
更新 2:MiniProfiler >=2
版本 2 中添加的 EF 内容破坏了我上面的 hack(它添加了一个仅供内部使用的IsActive
标志),这意味着我需要一种新方法:一个新的实现BaseProfilerProvider
对于异步任务:
public class TaskProfilerProvider<T> :
BaseProfilerProvider
{
Timing step;
MiniProfiler asyncProfiler;
public TaskProfilerProvider(Timing parentStep)
{
this.step = parentStep;
}
internal T Result { get; set; }
public override MiniProfiler GetCurrentProfiler()
{
return this.asyncProfiler;
}
public override MiniProfiler Start(ProfileLevel level)
{
var result = new MiniProfiler("TaskProfilerProvider<" + typeof(T).Name + ">", level);
this.asyncProfiler = result;
BaseProfilerProvider.SetProfilerActive(result);
return result;
}
public override void Stop(bool discardResults)
{
if (this.asyncProfiler == null)
{
return;
}
if (!BaseProfilerProvider.StopProfiler(this.asyncProfiler))
{
return;
}
if (discardResults)
{
this.asyncProfiler = null;
return;
}
BaseProfilerProvider.SaveProfiler(this.asyncProfiler);
}
public T SaveToParent()
{
// Add the timings from SQL to the current step
var asyncProfiler = this.GetCurrentProfiler();
foreach (var sqlTiming in asyncProfiler.GetSqlTimings())
{
this.step.AddSqlTiming(sqlTiming);
}
// Clear the results, they should have been copied to the main thread.
this.Stop(true);
return this.Result;
}
public static T SaveToParent(Task<TaskProfilerProvider<T>> continuedTask)
{
return continuedTask.Result.SaveToParent();
}
}
因此,要使用这个提供程序,我只需要在启动任务时启动它,并同步连接延续(像以前一样):
// Create a task that has its own profiler
var asyncTask = new Task<TaskProfilerProvider<T>>(
() =>
{
// Use the provider to start a new MiniProfiler
var result = new TaskProfilerProvider<T>(currentStep);
var asyncProfiler = result.Start(level);
result.Result = // ### Do long running SQL stuff ###
// Get the results
return result;
});
// When the task finishes continue on the main thread to add the SQL timings
var asyncWaiter = asyncTask.ContinueWith<T>(
TaskProfilerProvider<T>.SaveToParent,
TaskContinuationOptions.ExecuteSynchronously);
asyncTask.Start();
return asyncWaiter;
现在,SQL 计时与启动异步操作的步骤一致。这“%在sql中”虽然超过 100%,但额外的 82.4% 是通过并行执行 SQL 节省的时间。
duration (ms) from start (ms) query time (ms)
Start ...Async 0.0 +19.0 1 sql 4533.0
Wait for ...Async 4132.3 +421.3
182.4 % in sql
理想情况下,我会在等待步骤而不是初始化步骤上进行长时间运行的 SQL 查询,但我看不到一种方法可以在不更改调用方法的返回类型以显式传递计时的情况下执行此操作(这会使分析器更加引人注目)。