private DbConnectionPool GetConnectionPool(DbConnection owningObject, DbConnectionPoolGroup connectionPoolGroup)
        {
            // if poolgroup is disabled, it will be replaced with a new entry

            Debug.Assert(null != owningObject, "null owningObject?");
            Debug.Assert(null != connectionPoolGroup, "null connectionPoolGroup?");

            // It is possible that while the outer connection object has
            // been sitting around in a closed and unused state in some long
            // running app, the pruner may have come along and remove this
            // the pool entry from the master list.  If we were to use a
            // pool entry in this state, we would create "unmanaged" pools,
            // which would be bad.  To avoid this problem, we automagically
            // re-create the pool entry whenever it's disabled.

            // however, don't rebuild connectionOptions if no pooling is involved - let new connections do that work
            if (connectionPoolGroup.IsDisabled && (null != connectionPoolGroup.PoolGroupOptions))
            {
                // reusing existing pool option in case user originally used SetConnectionPoolOptions
                DbConnectionPoolGroupOptions poolOptions = connectionPoolGroup.PoolGroupOptions;

                // get the string to hash on again
                DbConnectionOptions connectionOptions = connectionPoolGroup.ConnectionOptions;
                Debug.Assert(null != connectionOptions, "prevent expansion of connectionString");

                connectionPoolGroup = GetConnectionPoolGroup(connectionPoolGroup.PoolKey, poolOptions, ref connectionOptions);
                Debug.Assert(null != connectionPoolGroup, "null connectionPoolGroup?");
                SetConnectionPoolGroup(owningObject, connectionPoolGroup);
            }
            DbConnectionPool connectionPool = connectionPoolGroup.GetConnectionPool(this);

            return(connectionPool);
        }
        private const int PoolGroupStateDisabled = 4; // factory pool entry prunning method

        internal DbConnectionPoolGroup(DbConnectionOptions connectionOptions, DbConnectionPoolKey key, DbConnectionPoolGroupOptions poolGroupOptions)
        {
            Debug.Assert(null != connectionOptions, "null connection options");

            _connectionOptions = connectionOptions;
            _poolKey           = key;
            _poolGroupOptions  = poolGroupOptions;

            // always lock this object before changing state
            // HybridDictionary does not create any sub-objects until add
            // so it is safe to use for non-pooled connection as long as
            // we check _poolGroupOptions first
            _poolCollection = new ConcurrentDictionary <DbConnectionPoolIdentity, DbConnectionPool>();
            _state          = PoolGroupStateActive;
        }
        // only created by DbConnectionPoolGroup.GetConnectionPool
        internal DbConnectionPool(
            DbConnectionFactory connectionFactory,
            DbConnectionPoolGroup connectionPoolGroup,
            DbConnectionPoolIdentity identity,
            DbConnectionPoolProviderInfo connectionPoolProviderInfo)
        {
            Debug.Assert(null != connectionPoolGroup, "null connectionPoolGroup");

            if ((null != identity) && identity.IsRestricted)
            {
                throw ADP.InternalError(ADP.InternalErrorCode.AttemptingToPoolOnRestrictedToken);
            }

            _state = State.Initializing;

            lock (s_random)
            {                                                     // Random.Next is not thread-safe
                _cleanupWait = s_random.Next(12, 24) * 10 * 1000; // 2-4 minutes in 10 sec intervals
            }

            _connectionFactory          = connectionFactory;
            _connectionPoolGroup        = connectionPoolGroup;
            _connectionPoolGroupOptions = connectionPoolGroup.PoolGroupOptions;
            _connectionPoolProviderInfo = connectionPoolProviderInfo;
            _identity = identity;

            _waitHandles = new PoolWaitHandles();

            _errorWait  = ERROR_WAIT_DEFAULT;
            _errorTimer = null;  // No error yet.

            _objectList = new List <DbConnectionInternal>(MaxPoolSize);

            _poolCreateRequest = new WaitCallback(PoolCreateRequest); // used by CleanupCallback
            _state             = State.Running;

            //_cleanupTimer & QueuePoolCreateRequest is delayed until DbConnectionPoolGroup calls
            // StartBackgroundCallbacks after pool is actually in the collection
        }
        internal DbConnectionPoolGroup GetConnectionPoolGroup(DbConnectionPoolKey key, DbConnectionPoolGroupOptions poolOptions, ref DbConnectionOptions userConnectionOptions)
        {
            if (ADP.IsEmpty(key.ConnectionString))
            {
                return((DbConnectionPoolGroup)null);
            }

            DbConnectionPoolGroup connectionPoolGroup;
            Dictionary <DbConnectionPoolKey, DbConnectionPoolGroup> connectionPoolGroups = _connectionPoolGroups;

            if (!connectionPoolGroups.TryGetValue(key, out connectionPoolGroup) || (connectionPoolGroup.IsDisabled && (null != connectionPoolGroup.PoolGroupOptions)))
            {
                // If we can't find an entry for the connection string in
                // our collection of pool entries, then we need to create a
                // new pool entry and add it to our collection.

                DbConnectionOptions connectionOptions = CreateConnectionOptions(key.ConnectionString, userConnectionOptions);
                if (null == connectionOptions)
                {
                    throw ADP.InternalConnectionError(ADP.ConnectionError.ConnectionOptionsMissing);
                }

                if (null == userConnectionOptions)
                { // we only allow one expansion on the connection string
                    userConnectionOptions = connectionOptions;
                }

                // We don't support connection pooling on Win9x
                if (null == poolOptions)
                {
                    if (null != connectionPoolGroup)
                    {
                        // reusing existing pool option in case user originally used SetConnectionPoolOptions
                        poolOptions = connectionPoolGroup.PoolGroupOptions;
                    }
                    else
                    {
                        // Note: may return null for non-pooled connections
                        poolOptions = CreateConnectionPoolGroupOptions(connectionOptions);
                    }
                }


                DbConnectionPoolGroup newConnectionPoolGroup = new DbConnectionPoolGroup(connectionOptions, key, poolOptions);
                newConnectionPoolGroup.ProviderInfo = CreateConnectionPoolGroupProviderInfo(connectionOptions);

                lock (this)
                {
                    connectionPoolGroups = _connectionPoolGroups;
                    if (!connectionPoolGroups.TryGetValue(key, out connectionPoolGroup))
                    {
                        // build new dictionary with space for new connection string
                        Dictionary <DbConnectionPoolKey, DbConnectionPoolGroup> newConnectionPoolGroups = new Dictionary <DbConnectionPoolKey, DbConnectionPoolGroup>(1 + connectionPoolGroups.Count);
                        foreach (KeyValuePair <DbConnectionPoolKey, DbConnectionPoolGroup> entry in connectionPoolGroups)
                        {
                            newConnectionPoolGroups.Add(entry.Key, entry.Value);
                        }

                        // lock prevents race condition with PruneConnectionPoolGroups
                        newConnectionPoolGroups.Add(key, newConnectionPoolGroup);
                        connectionPoolGroup   = newConnectionPoolGroup;
                        _connectionPoolGroups = newConnectionPoolGroups;
                    }
                    else
                    {
                        Debug.Assert(!connectionPoolGroup.IsDisabled, "Disabled pool entry discovered");
                    }
                }
                Debug.Assert(null != connectionPoolGroup, "how did we not create a pool entry?");
                Debug.Assert(null != userConnectionOptions, "how did we not have user connection options?");
            }
            else if (null == userConnectionOptions)
            {
                userConnectionOptions = connectionPoolGroup.ConnectionOptions;
            }
            return(connectionPoolGroup);
        }