Refactoring pool state and cross-instance access.

Author: mdaigle

src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj

@@ -83,6 +83,9 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionPool.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionPool.cs</Link>
     </Compile>
+    <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionPoolState.cs">
+      <Link>Microsoft\Data\ProviderBase\DbConnectionPoolState.cs</Link>
+    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionInternal.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionInternal.cs</Link>
     </Compile>

src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj

@@ -271,6 +271,9 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionPool.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionPool.cs</Link>
     </Compile>
+    <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionPoolState.cs">
+      <Link>Microsoft\Data\ProviderBase\DbConnectionPoolState.cs</Link>
+    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionPoolAuthenticationContext.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionPoolAuthenticationContext.cs</Link>
     </Compile>

src/Microsoft.Data.SqlClient/src/Microsoft/Data/ProviderBase/DbConnectionPool.cs

@@ -15,18 +15,12 @@
 using System.Transactions;
 using Microsoft.Data.Common;
 using Microsoft.Data.SqlClient;
+using static Microsoft.Data.ProviderBase.DbConnectionPoolState;
 
 namespace Microsoft.Data.ProviderBase
 {
-    internal sealed class DbConnectionPool : IDbConnectionPool
+    internal sealed class WaitHandleDbConnectionPool : DbConnectionPool
     {
-        private enum State
-        {
-            Initializing,
-            Running,
-            ShuttingDown,
-        }
-
         // This class is a way to stash our cloned Tx key for later disposal when it's no longer needed.
         // We can't get at the key in the dictionary without enumerating entries, so we stash an extra
         // copy as part of the value.
@@ -390,8 +384,6 @@ internal WaitHandle[] GetHandles(bool withCreate)
         /// </summary>
         private readonly ConcurrentDictionary<DbConnectionPoolAuthenticationContextKey, DbConnectionPoolAuthenticationContext> _pooledDbAuthenticationContexts;
 
-        private State _state;
-
         private readonly ConcurrentStack<DbConnectionInternal> _stackOld = new ConcurrentStack<DbConnectionInternal>();
         private readonly ConcurrentStack<DbConnectionInternal> _stackNew = new ConcurrentStack<DbConnectionInternal>();
 
@@ -417,7 +409,7 @@ internal WaitHandle[] GetHandles(bool withCreate)
         private int _totalObjects;
 
         // only created by DbConnectionPoolGroup.GetConnectionPool
-        internal DbConnectionPool(
+        internal WaitHandleDbConnectionPool(
                             DbConnectionFactory connectionFactory,
                             DbConnectionPoolGroup connectionPoolGroup,
                             DbConnectionPoolIdentity identity,
@@ -430,7 +422,7 @@ internal DbConnectionPool(
                 throw ADP.InternalError(ADP.InternalErrorCode.AttemptingToPoolOnRestrictedToken);
             }
 
-            _state = State.Initializing;
+            State = Initializing;
 
             lock (s_random)
             {
@@ -457,7 +449,7 @@ internal DbConnectionPool(
             _transactedConnectionPool = new TransactedConnectionPool(this);
 
             _poolCreateRequest = new WaitCallback(PoolCreateRequest); // used by CleanupCallback
-            _state = State.Running;
+            State = Running;
             SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.DbConnectionPool|RES|CPOOL> {0}, Constructed.", ObjectID);
 
             //_cleanupTimer & QueuePoolCreateRequest is delayed until DbConnectionPoolGroup calls
@@ -498,7 +490,7 @@ private bool NeedToReplenish
         {
             get
             {
-                if (State.Running != _state) // Don't allow connection create when not running.
+                if (State != Running) // Don't allow connection create when not running.
                     return false;
 
                 int totalObjects = Count;
@@ -524,7 +516,7 @@ internal override DbConnectionPoolIdentity Identity
 
         internal override bool IsRunning
         {
-            get { return State.Running == _state; }
+            get { return State == Running; }
         }
 
         private int MaxPoolSize
@@ -812,20 +804,6 @@ private DbConnectionInternal CreateObject(DbConnection owningObject, DbConnectio
 #endif
                 }
 
-                // If the old connection belonged to another pool, we need to remove it from that
-                if (oldConnection != null)
-                {
-                    var oldConnectionPool = oldConnection.Pool;
-                    if (oldConnectionPool != null && oldConnectionPool != this)
-                    {
-                        Debug.Assert(oldConnectionPool._state == State.ShuttingDown, "Old connections pool should be shutting down");
-                        lock (oldConnectionPool._objectList)
-                        {
-                            oldConnectionPool._objectList.Remove(oldConnection);
-                            oldConnectionPool._totalObjects = oldConnectionPool._objectList.Count;
-                        }
-                    }
-                }
                 SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.CreateObject|RES|CPOOL> {0}, Connection {1}, Added to pool.", ObjectID, newObj?.ObjectID);
 
                 // Reset the error wait:
@@ -913,7 +891,7 @@ private void DeactivateObject(DbConnectionInternal obj)
             {
                 // NOTE: constructor should ensure that current state cannot be State.Initializing, so it can only
                 //   be State.Running or State.ShuttingDown
-                Debug.Assert(_state == State.Running || _state == State.ShuttingDown);
+                Debug.Assert(State == Running || State == ShuttingDown);
 
                 lock (obj)
                 {
@@ -923,7 +901,7 @@ private void DeactivateObject(DbConnectionInternal obj)
                     // transaction object will ensure that it is owned (not lost),
                     // and it will be certain to put it back into the pool.                    
 
-                    if (_state == State.ShuttingDown)
+                    if (State == ShuttingDown)
                     {
                         if (obj.IsTransactionRoot)
                         {
@@ -1237,7 +1215,7 @@ internal override bool TryGetConnection(DbConnection owningObject, TaskCompletio
                 allowCreate = true;
             }
 
-            if (_state != State.Running)
+            if (State != Running)
             {
                 SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.GetConnection|RES|CPOOL> {0}, DbConnectionInternal State != Running.", ObjectID);
                 connection = null;
@@ -1615,7 +1593,7 @@ private void PoolCreateRequest(object state)
             long scopeID = SqlClientEventSource.Log.TryPoolerScopeEnterEvent("<prov.DbConnectionPool.PoolCreateRequest|RES|INFO|CPOOL> {0}", ObjectID);
             try
             {
-                if (State.Running == _state)
+                if (State == Running)
                 {
                     // in case WaitForPendingOpen ever failed with no subsequent OpenAsync calls,
                     // start it back up again
@@ -1804,7 +1782,7 @@ internal override void PutObjectFromTransactedPool(DbConnectionInternal obj)
             // done and all transactions are ended.
             SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.PutObjectFromTransactedPool|RES|CPOOL> {0}, Connection {1}, Transaction has ended.", ObjectID, obj.ObjectID);
 
-            if (_state == State.Running && obj.CanBePooled)
+            if (State == Running && obj.CanBePooled)
             {
                 PutNewObject(obj);
             }
@@ -1817,7 +1795,7 @@ internal override void PutObjectFromTransactedPool(DbConnectionInternal obj)
 
         private void QueuePoolCreateRequest()
         {
-            if (State.Running == _state)
+            if (State == Running)
             {
                 // Make sure we're at quota by posting a callback to the threadpool.
                 ThreadPool.QueueUserWorkItem(_poolCreateRequest);
@@ -1908,7 +1886,7 @@ internal override void Startup()
         internal override void Shutdown()
         {
             SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.Shutdown|RES|INFO|CPOOL> {0}", ObjectID);
-            _state = State.ShuttingDown;
+            State = ShuttingDown;
 
             // deactivate timer callbacks
             Timer t = _cleanupTimer;

src/Microsoft.Data.SqlClient/src/Microsoft/Data/ProviderBase/DbConnectionPoolGroup.cs

@@ -187,7 +187,7 @@ internal DbConnectionPool GetConnectionPool(DbConnectionFactory connectionFactor
                             if (!_poolCollection.TryGetValue(currentIdentity, out pool))
                             {
                                 DbConnectionPoolProviderInfo connectionPoolProviderInfo = connectionFactory.CreateConnectionPoolProviderInfo(ConnectionOptions);
-                                DbConnectionPool newPool = new(connectionFactory, this, currentIdentity, connectionPoolProviderInfo);
+                                DbConnectionPool newPool = new WaitHandleDbConnectionPool(connectionFactory, this, currentIdentity, connectionPoolProviderInfo);
 
                                 if (MarkPoolGroupAsActive())
                                 {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/ProviderBase/DbConnectionPoolState.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.Data.ProviderBase
+{
+    internal enum DbConnectionPoolState
+    {
+        Initializing,
+        Running,
+        ShuttingDown,
+    }
+}

src/Microsoft.Data.SqlClient/src/Microsoft/Data/ProviderBase/IDbConnectionPool.cs

@@ -11,7 +11,7 @@
 
 namespace Microsoft.Data.ProviderBase
 {
-    internal abstract class IDbConnectionPool
+    internal abstract class DbConnectionPool
     {
         private static int _objectTypeCount; // EventSource counter
         internal readonly int _objectID = System.Threading.Interlocked.Increment(ref _objectTypeCount);
@@ -24,6 +24,13 @@ internal int ObjectID
             }
         }
 
+        private DbConnectionPoolState _state;
+        internal DbConnectionPoolState State
+        {
+            get => _state;
+            set => _state = value;
+        }
+
         #region Abstract Properties
         internal abstract int Count
         {