do not use correlatio id as VsTelemetry will insert a session ID automatically.

src/Workspaces/Core/Portable/LinkedFileDiffMerging/LinkedFileDiffMergingLogger.cs

@@ -11,8 +11,7 @@ namespace Microsoft.CodeAnalysis
 {
     internal class LinkedFileDiffMergingLogger
     {
-        private const string Id = nameof(Id);
-        private static ConcurrentDictionary<int, LogAggregator> LogAggregators = new ConcurrentDictionary<int, LogAggregator>();
+        private static LogAggregator LogAggregator = new LogAggregator();
 
         internal enum MergeInfo
         {
@@ -31,98 +30,70 @@ internal static void LogSession(Workspace workspace, LinkedFileDiffMergingSessio
         {
             if (sessionInfo.LinkedFileGroups.Count > 1)
             {
-                int correlationId = GetCorrelationId(workspace);
-
-                LogNewSessionWithLinkedFiles(correlationId);
-                LogNumberOfLinkedFileGroupsProcessed(correlationId, sessionInfo.LinkedFileGroups.Count);
+                LogNewSessionWithLinkedFiles();
+                LogNumberOfLinkedFileGroupsProcessed(sessionInfo.LinkedFileGroups.Count);
 
                 foreach (var groupInfo in sessionInfo.LinkedFileGroups)
                 {
-                    LogNumberOfIdenticalDiffs(correlationId, groupInfo.IdenticalDiffs);
-                    LogNumberOfIsolatedDiffs(correlationId, groupInfo.IsolatedDiffs);
-                    LogNumberOfOverlappingDistinctDiffs(correlationId, groupInfo.OverlappingDistinctDiffs);
-                    LogNumberOfOverlappingDistinctDiffsWithSameSpan(correlationId, groupInfo.OverlappingDistinctDiffsWithSameSpan);
-                    LogNumberOfOverlappingDistinctDiffsWithSameSpanAndSubstringRelation(correlationId, groupInfo.OverlappingDistinctDiffsWithSameSpanAndSubstringRelation);
-                    LogNumberOfInsertedMergeConflictComments(correlationId, groupInfo.InsertedMergeConflictComments);
-                    LogNumberOfInsertedMergeConflictCommentsAtAdjustedLocation(correlationId, groupInfo.InsertedMergeConflictCommentsAtAdjustedLocation);
+                    LogNumberOfIdenticalDiffs(groupInfo.IdenticalDiffs);
+                    LogNumberOfIsolatedDiffs(groupInfo.IsolatedDiffs);
+                    LogNumberOfOverlappingDistinctDiffs(groupInfo.OverlappingDistinctDiffs);
+                    LogNumberOfOverlappingDistinctDiffsWithSameSpan(groupInfo.OverlappingDistinctDiffsWithSameSpan);
+                    LogNumberOfOverlappingDistinctDiffsWithSameSpanAndSubstringRelation(groupInfo.OverlappingDistinctDiffsWithSameSpanAndSubstringRelation);
+                    LogNumberOfInsertedMergeConflictComments(groupInfo.InsertedMergeConflictComments);
+                    LogNumberOfInsertedMergeConflictCommentsAtAdjustedLocation(groupInfo.InsertedMergeConflictCommentsAtAdjustedLocation);
 
                     if (groupInfo.InsertedMergeConflictComments > 0 ||
                         groupInfo.InsertedMergeConflictCommentsAtAdjustedLocation > 0)
                     {
-                        Logger.Log(FunctionId.Workspace_Solution_LinkedFileDiffMergingSession_LinkedFileGroup, SessionLogMessage.Create(correlationId, groupInfo));
+                        Logger.Log(FunctionId.Workspace_Solution_LinkedFileDiffMergingSession_LinkedFileGroup, SessionLogMessage.Create(groupInfo));
                     }
                 }
             }
         }
 
-        private static int GetCorrelationId(Workspace workspace)
-        {
-            int correlationId = workspace.GetHashCode();
-            if (!LogAggregators.Keys.Contains(correlationId))
-            {
-                LogAggregators.TryAdd(correlationId, new LogAggregator());
-            }
-
-            return correlationId;
-        }
-
-        private static void LogNewSessionWithLinkedFiles(int correlationId) =>
-            Log(correlationId, (int)MergeInfo.SessionsWithLinkedFiles, 1);
-
-        private static void LogNumberOfLinkedFileGroupsProcessed(int correlationId, int linkedFileGroupsProcessed) =>
-            Log(correlationId, (int)MergeInfo.LinkedFileGroupsProcessed, linkedFileGroupsProcessed);
+        private static void LogNewSessionWithLinkedFiles() =>
+            Log((int)MergeInfo.SessionsWithLinkedFiles, 1);
 
-        private static void LogNumberOfIdenticalDiffs(int correlationId, int identicalDiffs) =>
-            Log(correlationId, (int)MergeInfo.IdenticalDiffs, identicalDiffs);
+        private static void LogNumberOfLinkedFileGroupsProcessed(int linkedFileGroupsProcessed) =>
+            Log((int)MergeInfo.LinkedFileGroupsProcessed, linkedFileGroupsProcessed);
 
-        private static void LogNumberOfIsolatedDiffs(int correlationId, int isolatedDiffs) =>
-            Log(correlationId, (int)MergeInfo.IsolatedDiffs, isolatedDiffs);
+        private static void LogNumberOfIdenticalDiffs(int identicalDiffs) =>
+            Log((int)MergeInfo.IdenticalDiffs, identicalDiffs);
 
-        private static void LogNumberOfOverlappingDistinctDiffs(int correlationId, int overlappingDistinctDiffs) =>
-            Log(correlationId, (int)MergeInfo.OverlappingDistinctDiffs, overlappingDistinctDiffs);
+        private static void LogNumberOfIsolatedDiffs(int isolatedDiffs) =>
+            Log((int)MergeInfo.IsolatedDiffs, isolatedDiffs);
 
-        private static void LogNumberOfOverlappingDistinctDiffsWithSameSpan(int correlationId, int overlappingDistinctDiffsWithSameSpan) =>
-            Log(correlationId, (int)MergeInfo.OverlappingDistinctDiffsWithSameSpan, overlappingDistinctDiffsWithSameSpan);
+        private static void LogNumberOfOverlappingDistinctDiffs(int overlappingDistinctDiffs) =>
+            Log((int)MergeInfo.OverlappingDistinctDiffs, overlappingDistinctDiffs);
 
-        private static void LogNumberOfOverlappingDistinctDiffsWithSameSpanAndSubstringRelation(int correlationId, int overlappingDistinctDiffsWithSameSpanAndSubstringRelation) =>
-            Log(correlationId, (int)MergeInfo.OverlappingDistinctDiffsWithSameSpanAndSubstringRelation, overlappingDistinctDiffsWithSameSpanAndSubstringRelation);
+        private static void LogNumberOfOverlappingDistinctDiffsWithSameSpan(int overlappingDistinctDiffsWithSameSpan) =>
+            Log((int)MergeInfo.OverlappingDistinctDiffsWithSameSpan, overlappingDistinctDiffsWithSameSpan);
 
-        private static void LogNumberOfInsertedMergeConflictComments(int correlationId, int insertedMergeConflictComments) =>
-            Log(correlationId, (int)MergeInfo.InsertedMergeConflictComments, insertedMergeConflictComments);
+        private static void LogNumberOfOverlappingDistinctDiffsWithSameSpanAndSubstringRelation(int overlappingDistinctDiffsWithSameSpanAndSubstringRelation) =>
+            Log((int)MergeInfo.OverlappingDistinctDiffsWithSameSpanAndSubstringRelation, overlappingDistinctDiffsWithSameSpanAndSubstringRelation);
 
-        private static void LogNumberOfInsertedMergeConflictCommentsAtAdjustedLocation(int correlationId, int insertedMergeConflictCommentsAtAdjustedLocation) =>
-            Log(correlationId, (int)MergeInfo.InsertedMergeConflictCommentsAtAdjustedLocation, insertedMergeConflictCommentsAtAdjustedLocation);
+        private static void LogNumberOfInsertedMergeConflictComments(int insertedMergeConflictComments) =>
+            Log((int)MergeInfo.InsertedMergeConflictComments, insertedMergeConflictComments);
 
-        private static void Log(int correlationId, int mergeInfo, int count)
-        {
-            LogAggregators[correlationId].IncreaseCountBy(mergeInfo, count);
-        }
+        private static void LogNumberOfInsertedMergeConflictCommentsAtAdjustedLocation(int insertedMergeConflictCommentsAtAdjustedLocation) =>
+            Log((int)MergeInfo.InsertedMergeConflictCommentsAtAdjustedLocation, insertedMergeConflictCommentsAtAdjustedLocation);
 
-        internal static void ReportTelemetry(int correlationId)
+        private static void Log(int mergeInfo, int count)
         {
-            if (LogAggregators.ContainsKey(correlationId))
-            {
-                Logger.Log(FunctionId.Workspace_Solution_LinkedFileDiffMergingSession, KeyValueLogMessage.Create(m =>
-                {
-                    m[Id] = correlationId;
-
-                    foreach (var kv in LogAggregators[correlationId])
-                    {
-                        var mergeInfo = ((MergeInfo)kv.Key).ToString("f");
-                        m[mergeInfo] = kv.Value.GetCount();
-                    }
-                }));
-                LogAggregator value;
-                LogAggregators.TryRemove(correlationId, out value);
-            }
+            LogAggregator.IncreaseCountBy(mergeInfo, count);
         }
 
         internal static void ReportTelemetry()
         {
-            foreach (var correlationId in LogAggregators.Keys)
+            Logger.Log(FunctionId.Workspace_Solution_LinkedFileDiffMergingSession, KeyValueLogMessage.Create(m =>
             {
-                ReportTelemetry(correlationId);
-            }
+                foreach (var kv in LogAggregator)
+                {
+                    var mergeInfo = ((MergeInfo)kv.Key).ToString("f");
+                    m[mergeInfo] = kv.Value.GetCount();
+                }
+            }));
         }
 
         private static class SessionLogMessage
@@ -130,12 +101,10 @@ private static class SessionLogMessage
             private const string LinkedDocuments = nameof(LinkedDocuments);
             private const string DocumentsWithChanges = nameof(DocumentsWithChanges);
 
-            public static KeyValueLogMessage Create(int correlationId, LinkedFileGroupSessionInfo groupInfo)
+            public static KeyValueLogMessage Create(LinkedFileGroupSessionInfo groupInfo)
             {
                 return KeyValueLogMessage.Create(m =>
                 {
-                    m[Id] = correlationId;
-
                     m[LinkedDocuments] = groupInfo.LinkedDocuments;
                     m[DocumentsWithChanges] = groupInfo.DocumentsWithChanges;
                     m[MergeInfo.IdenticalDiffs.ToString("f")] = groupInfo.IdenticalDiffs;