Move Command start/stop out of NpgsqlEventSource (#3023)

roji · web-flow · commit 209494ff86d6 · 2020-06-16T14:24:14.000+02:00
Fixes #3022
diff --git a/src/Npgsql/NpgsqlEventSource.cs b/src/Npgsql/NpgsqlEventSource.cs
@@ -55,15 +55,15 @@ public void CommandStart(string sql)
         {
             Interlocked.Increment(ref _totalCommands);
             Interlocked.Increment(ref _currentCommands);
-            WriteEvent(CommandStartId, sql);
+            NpgsqlSqlEventSource.CommandStart(sql);
         }
 
         [MethodImpl(MethodImplOptions.NoInlining)]
         [Event(CommandStopId, Level = EventLevel.Informational)]
         public void CommandStop()
         {
             Interlocked.Decrement(ref _currentCommands);
-            WriteEvent(CommandStopId);
+            NpgsqlSqlEventSource.CommandStop();
         }
 
         internal void CommandStartPrepared() => Interlocked.Increment(ref _totalPreparedCommands);
diff --git a/src/Npgsql/NpgsqlSqlEventSource.cs b/src/Npgsql/NpgsqlSqlEventSource.cs
@@ -0,0 +1,31 @@
+using System.Diagnostics.Tracing;
+using System.Runtime.CompilerServices;
+
+namespace Npgsql
+{
+    sealed class NpgsqlSqlEventSource : EventSource
+    {
+        static readonly NpgsqlSqlEventSource Log = new NpgsqlSqlEventSource();
+
+        const string EventSourceName = "Npgsql.Sql";
+
+        const int CommandStartId = 3;
+        const int CommandStopId = 4;
+
+        internal NpgsqlSqlEventSource() : base(EventSourceName) {}
+
+        // NOTE
+        // - The 'Start' and 'Stop' suffixes on the following event names have special meaning in EventSource. They
+        //   enable creating 'activities'.
+        //   For more information, take a look at the following blog post:
+        //   https://blogs.msdn.microsoft.com/vancem/2015/09/14/exploring-eventsource-activity-correlation-and-causation-features/
+        // - A stop event's event id must be next one after its start event.
+
+        [Event(CommandStartId, Level = EventLevel.Informational)]
+        public static void CommandStart(string sql) => Log.WriteEvent(CommandStartId, sql);
+
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        [Event(CommandStopId, Level = EventLevel.Informational)]
+        public static void CommandStop() => Log.WriteEvent(CommandStopId);
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -55,15 +55,15 @@ public void CommandStart(string sql)`
`55`	`55`	`{`
`56`	`56`	`Interlocked.Increment(ref _totalCommands);`
`57`	`57`	`Interlocked.Increment(ref _currentCommands);`
`58`		`- WriteEvent(CommandStartId, sql);`
	`58`	`+ NpgsqlSqlEventSource.CommandStart(sql);`
`59`	`59`	`}`
`60`	`60`
`61`	`61`	`[MethodImpl(MethodImplOptions.NoInlining)]`
`62`	`62`	`[Event(CommandStopId, Level = EventLevel.Informational)]`
`63`	`63`	`public void CommandStop()`
`64`	`64`	`{`
`65`	`65`	`Interlocked.Decrement(ref _currentCommands);`
`66`		`- WriteEvent(CommandStopId);`
	`66`	`+ NpgsqlSqlEventSource.CommandStop();`
`67`	`67`	`}`
`68`	`68`
`69`	`69`	`internal void CommandStartPrepared() => Interlocked.Increment(ref _totalPreparedCommands);`