diff --git a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/Common/AdapterUtil.SqlClient.cs b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/Common/AdapterUtil.SqlClient.cs
index da6a069c90..279c310d10 100644
--- a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/Common/AdapterUtil.SqlClient.cs
+++ b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/Common/AdapterUtil.SqlClient.cs
@@ -757,29 +757,37 @@ internal static Version GetAssemblyVersion()
         // This method assumes dataSource parameter is in TCP connection string format.
         internal static bool IsAzureSqlServerEndpoint(string dataSource)
         {
+            int length = dataSource.Length;
             // remove server port
-            int i = dataSource.LastIndexOf(',');
-            if (i >= 0)
+            int foundIndex = dataSource.LastIndexOf(',');
+            if (foundIndex >= 0)
             {
-                dataSource = dataSource.Substring(0, i);
+                length = foundIndex;
             }
 
             // check for the instance name
-            i = dataSource.LastIndexOf('\\');
-            if (i >= 0)
+            foundIndex = dataSource.LastIndexOf('\\', length - 1, length - 1);
+            if (foundIndex > 0)
             {
-                dataSource = dataSource.Substring(0, i);
+                length = foundIndex;
             }
 
-            // trim redundant whitespace
-            dataSource = dataSource.Trim();
+            // trim trailing whitespace
+            while (length > 0 && char.IsWhiteSpace(dataSource[length - 1]))
+            {
+                length -= 1;
+            }
 
             // check if servername end with any azure endpoints
-            for (i = 0; i < AzureSqlServerEndpoints.Length; i++)
+            for (int index = 0; index < AzureSqlServerEndpoints.Length; index++)
             {
-                if (dataSource.EndsWith(AzureSqlServerEndpoints[i], StringComparison.OrdinalIgnoreCase))
+                string endpoint = AzureSqlServerEndpoints[index];
+                if (length > endpoint.Length)
                 {
-                    return true;
+                    if (string.Compare(dataSource, length - endpoint.Length, endpoint, 0, endpoint.Length, StringComparison.OrdinalIgnoreCase) == 0)
+                    {
+                        return true;
+                    }
                 }
             }
 
diff --git a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
index 925f5a4f1b..c2e41d4cb3 100644
--- a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
+++ b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserStateObject.cs
@@ -135,6 +135,7 @@ public TimeoutState(int value)
         private volatile int _timeoutIdentityValue;
         internal volatile bool _attentionSent;              // true if we sent an Attention to the server
         internal volatile bool _attentionSending;
+        private readonly TimerCallback _onTimeoutAsync;
 
         // Below 2 properties are used to enforce timeout delays in code to 
         // reproduce issues related to theadpool starvation and timeout delay.
@@ -293,6 +294,7 @@ internal TdsParserStateObject(TdsParser parser)
             // Construct a physical connection
             Debug.Assert(null != parser, "no parser?");
             _parser = parser;
+            _onTimeoutAsync = OnTimeoutAsync;
 
             // For physical connection, initialize to default login packet size.
             SetPacketSize(TdsEnums.DEFAULT_LOGIN_PACKET_SIZE);
@@ -309,6 +311,7 @@ internal TdsParserStateObject(TdsParser parser, TdsParserStateObject physicalCon
             // Construct a MARS session
             Debug.Assert(null != parser, "no parser?");
             _parser = parser;
+            _onTimeoutAsync = OnTimeoutAsync;
             SniContext = SniContext.Snix_GetMarsSession;
 
             Debug.Assert(null != _parser._physicalStateObj, "no physical session?");
@@ -2474,7 +2477,7 @@ internal void ReadSni(TaskCompletionSource<object> completion)
                 _networkPacketTimeout?.Dispose();
 
                 _networkPacketTimeout = ADP.UnsafeCreateTimer(
-                    new TimerCallback(OnTimeoutAsync),
+                    _onTimeoutAsync,
                     new TimeoutState(_timeoutIdentityValue),
                     Timeout.Infinite,
                     Timeout.Infinite
diff --git a/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientEventSource.cs b/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientEventSource.cs
index 045b8c7eba..abee56fe5b 100644
--- a/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientEventSource.cs
+++ b/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/SqlClientEventSource.cs
@@ -449,7 +449,7 @@ internal void TryScopeLeaveEvent(long scopeId)
 
         #region Execution Trace
         [NonEvent]
-        internal void TryBeginExecuteEvent(int objectId, object connectionId, string commandText, [System.Runtime.CompilerServices.CallerMemberName] string memberName = "")
+        internal void TryBeginExecuteEvent(int objectId, Guid? connectionId, string commandText, [System.Runtime.CompilerServices.CallerMemberName] string memberName = "")
         {
             if (Log.IsExecutionTraceEnabled())
             {
@@ -459,7 +459,7 @@ internal void TryBeginExecuteEvent(int objectId, object connectionId, string com
         }
 
         [NonEvent]
-        internal void TryEndExecuteEvent(int objectId, object connectionId, int compositeState, int sqlExceptionNumber, [System.Runtime.CompilerServices.CallerMemberName] string memberName = "")
+        internal void TryEndExecuteEvent(int objectId, Guid? connectionId, int compositeState, int sqlExceptionNumber, [System.Runtime.CompilerServices.CallerMemberName] string memberName = "")
         {
             if (Log.IsExecutionTraceEnabled())
             {