Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / whidbey / netfxsp / ndp / fx / src / Data / System / Data / ProviderBase / DbConnectionFactory.cs / 2 / DbConnectionFactory.cs
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// [....]
//-----------------------------------------------------------------------------
namespace System.Data.ProviderBase {
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Data.Common;
using System.Threading;
#if ORACLE
using System.Data.OracleClient;
#endif
internal abstract class DbConnectionFactory {
private Dictionary _connectionPoolGroups;
private readonly List _poolsToRelease;
private readonly List _poolGroupsToRelease;
private readonly DbConnectionPoolCounters _performanceCounters;
private readonly Timer _pruningTimer;
private const int PruningDueTime =4*60*1000; // 4 minutes
private const int PruningPeriod = 30*1000; // thirty seconds
private static int _objectTypeCount; // Bid counter
internal readonly int _objectID = System.Threading.Interlocked.Increment(ref _objectTypeCount);
protected DbConnectionFactory() : this (DbConnectionPoolCountersNoCounters.SingletonInstance) { }
protected DbConnectionFactory(DbConnectionPoolCounters performanceCounters) {
_performanceCounters = performanceCounters;
_connectionPoolGroups = new Dictionary();
_poolsToRelease = new List();
_poolGroupsToRelease = new List();
_pruningTimer = CreatePruningTimer();
}
internal DbConnectionPoolCounters PerformanceCounters {
get { return _performanceCounters; }
}
abstract public DbProviderFactory ProviderFactory {
get;
}
internal int ObjectID {
get {
return _objectID;
}
}
public void ClearAllPools() {
IntPtr hscp;
Bid.ScopeEnter(out hscp, " ");
try {
Dictionary connectionPoolGroups = _connectionPoolGroups;
foreach (KeyValuePair entry in connectionPoolGroups) {
DbConnectionPoolGroup poolGroup = entry.Value;
if (null != poolGroup) {
Debug.Assert(!poolGroup.IsDisabled, "Disabled pool entry discovered");
poolGroup.Clear();
}
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
}
public void ClearPool(DbConnection connection) {
ADP.CheckArgumentNull(connection, "connection");
IntPtr hscp;
Bid.ScopeEnter(out hscp, " %d#" , GetObjectId(connection));
try {
DbConnectionPoolGroup poolGroup = GetConnectionPoolGroup(connection);
if (null != poolGroup) {
poolGroup.Clear();
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
}
#if !ORACLE
public void ClearPool(string connectionString) {
ADP.CheckArgumentNull(connectionString, "connectionString");
IntPtr hscp;
Bid.ScopeEnter(out hscp, " connectionString");
try {
DbConnectionPoolGroup poolGroup;
Dictionary connectionPoolGroups = _connectionPoolGroups;
if (connectionPoolGroups.TryGetValue(connectionString, out poolGroup)) {
poolGroup.Clear();
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
}
#endif
internal virtual DbConnectionPoolProviderInfo CreateConnectionPoolProviderInfo(DbConnectionOptions connectionOptions){
return null;
}
virtual protected DbMetaDataFactory CreateMetaDataFactory(DbConnectionInternal internalConnection, out bool cacheMetaDataFactory) {
// providers that support GetSchema must override this with a method that creates a meta data
// factory appropriate for them.
cacheMetaDataFactory = false;
throw ADP.NotSupported();
}
internal DbConnectionInternal CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup) {
Debug.Assert(null != owningConnection, "null owningConnection?");
Debug.Assert(null != poolGroup, "null poolGroup?");
DbConnectionOptions connectionOptions = poolGroup.ConnectionOptions;
DbConnectionPoolGroupProviderInfo poolGroupProviderInfo = poolGroup.ProviderInfo;
DbConnectionInternal newConnection = CreateConnection(connectionOptions, poolGroupProviderInfo, null, owningConnection);
if (null != newConnection) {
PerformanceCounters.HardConnectsPerSecond.Increment();
newConnection.MakeNonPooledObject(owningConnection, PerformanceCounters);
}
Bid.Trace(" %d#, Non-pooled database connection created.\n", ObjectID);
return newConnection;
}
internal DbConnectionInternal CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) {
Debug.Assert(null != pool, "null pool?");
DbConnectionPoolGroupProviderInfo poolGroupProviderInfo = pool.PoolGroup.ProviderInfo;
DbConnectionInternal newConnection = CreateConnection(options, poolGroupProviderInfo, pool, owningConnection);
if (null != newConnection) {
PerformanceCounters.HardConnectsPerSecond.Increment();
newConnection.MakePooledConnection(pool);
}
Bid.Trace(" %d#, Pooled database connection created.\n", ObjectID);
return newConnection;
}
virtual internal DbConnectionPoolGroupProviderInfo CreateConnectionPoolGroupProviderInfo (DbConnectionOptions connectionOptions) {
return null;
}
private Timer CreatePruningTimer() {
TimerCallback callback = new TimerCallback(PruneConnectionPoolGroups);
return new Timer(callback, null, PruningDueTime, PruningPeriod);
}
#if !ORACLE
protected DbConnectionOptions FindConnectionOptions(string connectionString) {
if (!ADP.IsEmpty(connectionString)) {
DbConnectionPoolGroup connectionPoolGroup;
Dictionary connectionPoolGroups = _connectionPoolGroups;
if (connectionPoolGroups.TryGetValue(connectionString, out connectionPoolGroup)) {
return connectionPoolGroup.ConnectionOptions;
}
}
return null;
}
#endif
internal DbConnectionInternal GetConnection(DbConnection owningConnection) {
Debug.Assert(null != owningConnection, "null owningConnection?");
DbConnectionPoolGroup poolGroup;
DbConnectionPool connectionPool;
DbConnectionInternal connection;
// SQLBU 431251:
// Work around race condition with clearing the pool between GetConnectionPool obtaining pool
// and GetConnection on the pool checking the pool state. Clearing the pool in this window
// will switch the pool into the ShuttingDown state, and GetConnection will return null.
// There is probably a better solution involving locking the pool/group, but that entails a major
// re-design of the connection pooling synchronization, so is post-poned for now.
// use retriesLeft to prevent CPU spikes
int retriesLeft = 5;
do {
poolGroup = GetConnectionPoolGroup(owningConnection);
connectionPool = GetConnectionPool(owningConnection, poolGroup);
if (null == connectionPool) {
// If GetConnectionPool returns null, we can be certain that
// this connection should not be pooled via DbConnectionPool
// or have a disabled pool entry.
poolGroup = GetConnectionPoolGroup(owningConnection); // previous entry have been disabled
connection = CreateNonPooledConnection(owningConnection, poolGroup);
PerformanceCounters.NumberOfNonPooledConnections.Increment();
}
else {
connection = connectionPool.GetConnection(owningConnection);
if (connection != null) {
// we are done
break;
}
// connection creation failed on semaphore waiting or if max pool reached
if (connectionPool.IsRunning) {
// If GetConnection failed while the pool is running, the pool timeout occurred.
Bid.Trace(" %d#, GetConnection failed because a pool timeout occurred.\n", ObjectID);
throw ADP.PooledOpenTimeout();
}
else {
// We've hit the race condition, where the pool was shut down after we got it from the group.
// Yield time slice to allow shut down activities to complete and a new, running pool to be instantiated
// before retrying.
Threading.Thread.Sleep(1);
}
}
} while (connection == null && (retriesLeft--) > 0);
if (connection == null) {
// exhausted all retries or timed out - give up
Bid.Trace(" %d#, GetConnection failed because a pool timeout occurred and all retries were exhausted.\n", ObjectID);
throw ADP.PooledOpenTimeout();
}
return connection;
}
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)) {
Bid.Trace(" %d#, DisabledPoolGroup=%d#\n", ObjectID, connectionPoolGroup.ObjectID);
// 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;
string connectionString = connectionOptions.UsersConnectionString(false);
Debug.Assert(null != connectionOptions, "prevent expansion of connectionString");
connectionPoolGroup = GetConnectionPoolGroup(connectionString, poolOptions, ref connectionOptions);
Debug.Assert(null != connectionPoolGroup, "null connectionPoolGroup?");
SetConnectionPoolGroup(owningObject, connectionPoolGroup);
}
DbConnectionPool connectionPool = connectionPoolGroup.GetConnectionPool(this);
return connectionPool;
}
internal DbConnectionPoolGroup GetConnectionPoolGroup(string connectionString, DbConnectionPoolGroupOptions poolOptions, ref DbConnectionOptions userConnectionOptions) {
if (ADP.IsEmpty(connectionString)) {
return (DbConnectionPoolGroup)null;
}
DbConnectionPoolGroup connectionPoolGroup;
Dictionary connectionPoolGroups = _connectionPoolGroups;
if (!connectionPoolGroups.TryGetValue(connectionString, 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(connectionString, userConnectionOptions);
if (null == connectionOptions) {
throw ADP.InternalConnectionError(ADP.ConnectionError.ConnectionOptionsMissing);
}
string expandedConnectionString = connectionString;
if (null == userConnectionOptions) { // we only allow one expansion on the connection string
userConnectionOptions = connectionOptions;
expandedConnectionString = connectionOptions.Expand();
// if the expanded string is same instance (default implementation), the use the already created options
if ((object)expandedConnectionString != (object)connectionString) {
//
return GetConnectionPoolGroup(expandedConnectionString, null, ref userConnectionOptions);
}
}
// We don't support connection pooling on Win9x; it lacks too many of the APIs we require.
if ((null == poolOptions) && ADP.IsWindowsNT) {
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, poolOptions);
newConnectionPoolGroup.ProviderInfo = CreateConnectionPoolGroupProviderInfo(connectionOptions);
lock (this) {
connectionPoolGroups = _connectionPoolGroups;
if (!connectionPoolGroups.TryGetValue(expandedConnectionString, out connectionPoolGroup)) {
// build new dictionary with space for new connection string
Dictionary newConnectionPoolGroups = new Dictionary(1+connectionPoolGroups.Count);
foreach (KeyValuePair entry in connectionPoolGroups) {
newConnectionPoolGroups.Add(entry.Key, entry.Value);
}
// lock prevents race condition with PruneConnectionPoolGroups
newConnectionPoolGroups.Add(expandedConnectionString, newConnectionPoolGroup);
PerformanceCounters.NumberOfActiveConnectionPoolGroups.Increment();
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;
}
internal DbMetaDataFactory GetMetaDataFactory(DbConnectionPoolGroup connectionPoolGroup,DbConnectionInternal internalConnection){
Debug.Assert (connectionPoolGroup != null, "connectionPoolGroup may not be null.");
// get the matadatafactory from the pool entry. If it does not already have one
// create one and save it on the pool entry
DbMetaDataFactory metaDataFactory = connectionPoolGroup.MetaDataFactory;
// consider serializing this so we don't construct multiple metadata factories
// if two threads happen to hit this at the same time. One will be GC'd
if (metaDataFactory == null){
bool allowCache = false;
metaDataFactory = CreateMetaDataFactory(internalConnection, out allowCache);
if (allowCache) {
connectionPoolGroup.MetaDataFactory = metaDataFactory;
}
}
return metaDataFactory;
}
private void PruneConnectionPoolGroups(object state) {
// when debugging this method, expect multiple threads at the same time
if (Bid.AdvancedOn) {
Bid.Trace(" %d#\n", ObjectID);
}
// First, walk the pool release list and attempt to clear each
// pool, when the pool is finally empty, we dispose of it. If the
// pool isn't empty, it's because there are active connections or
// distributed transactions that need it.
lock (_poolsToRelease) {
if (0 != _poolsToRelease.Count) {
DbConnectionPool[] poolsToRelease = _poolsToRelease.ToArray();
foreach (DbConnectionPool pool in poolsToRelease) {
if (null != pool) {
pool.Clear();
if (0 == pool.Count) {
_poolsToRelease.Remove(pool);
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, ReleasePool=%d#\n", ObjectID, pool.ObjectID);
}
PerformanceCounters.NumberOfInactiveConnectionPools.Decrement();
}
}
}
}
}
// Next, walk the pool entry release list and dispose of each
// pool entry when it is finally empty. If the pool entry isn't
// empty, it's because there are active pools that need it.
lock (_poolGroupsToRelease) {
if (0 != _poolGroupsToRelease.Count) {
DbConnectionPoolGroup[] poolGroupsToRelease = _poolGroupsToRelease.ToArray();
foreach (DbConnectionPoolGroup poolGroup in poolGroupsToRelease) {
if (null != poolGroup) {
poolGroup.Clear(); // may add entries to _poolsToRelease
if (0 == poolGroup.Count) {
_poolGroupsToRelease.Remove(poolGroup);
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, ReleasePoolGroup=%d#\n", ObjectID, poolGroup.ObjectID);
}
PerformanceCounters.NumberOfInactiveConnectionPoolGroups.Decrement();
}
}
}
}
}
// Finally, we walk through the collection of connection pool entries
// and prune each one. This will cause any empty pools to be put
// into the release list.
lock (this) {
Dictionary connectionPoolGroups = _connectionPoolGroups;
Dictionary newConnectionPoolGroups = new Dictionary(connectionPoolGroups.Count);
foreach (KeyValuePair entry in connectionPoolGroups) {
if (null != entry.Value) {
Debug.Assert(!entry.Value.IsDisabled, "Disabled pool entry discovered");
// entries start active and go idle during prune if all pools are gone
// move idle entries from last prune pass to a queue for pending release
// otherwise process entry which may move it from active to idle
if (entry.Value.Prune()) { // may add entries to _poolsToRelease
PerformanceCounters.NumberOfActiveConnectionPoolGroups.Decrement();
QueuePoolGroupForRelease(entry.Value);
}
else {
newConnectionPoolGroups.Add(entry.Key, entry.Value);
}
}
}
_connectionPoolGroups = newConnectionPoolGroups;
}
}
internal void QueuePoolForRelease(DbConnectionPool pool, bool clearing) {
// Queue the pool up for release -- we'll clear it out and dispose
// of it as the last part of the pruning timer callback so we don't
// do it with the pool entry or the pool collection locked.
Debug.Assert (null != pool, "null pool?");
// set the pool to the shutdown state to force all active
// connections to be automatically disposed when they
// are returned to the pool
pool.Shutdown();
lock (_poolsToRelease) {
if (clearing) {
pool.Clear();
}
_poolsToRelease.Add(pool);
}
PerformanceCounters.NumberOfInactiveConnectionPools.Increment();
}
internal void QueuePoolGroupForRelease(DbConnectionPoolGroup poolGroup) {
Debug.Assert (null != poolGroup, "null poolGroup?");
Bid.Trace(" %d#, poolGroup=%d#\n", ObjectID, poolGroup.ObjectID);
lock (_poolGroupsToRelease) {
_poolGroupsToRelease.Add(poolGroup);
}
PerformanceCounters.NumberOfInactiveConnectionPoolGroups.Increment();
}
abstract protected DbConnectionInternal CreateConnection(DbConnectionOptions options, object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection);
abstract protected DbConnectionOptions CreateConnectionOptions(string connectionString, DbConnectionOptions previous);
abstract protected DbConnectionPoolGroupOptions CreateConnectionPoolGroupOptions(DbConnectionOptions options);
abstract internal DbConnectionPoolGroup GetConnectionPoolGroup(DbConnection connection);
abstract internal DbConnectionInternal GetInnerConnection(DbConnection connection);
abstract protected int GetObjectId(DbConnection connection);
abstract internal void PermissionDemand(DbConnection outerConnection);
abstract internal void SetConnectionPoolGroup(DbConnection outerConnection, DbConnectionPoolGroup poolGroup);
abstract internal void SetInnerConnectionEvent(DbConnection owningObject, DbConnectionInternal to);
abstract internal bool SetInnerConnectionFrom(DbConnection owningObject, DbConnectionInternal to, DbConnectionInternal from) ;
abstract internal void SetInnerConnectionTo(DbConnection owningObject, DbConnectionInternal to);
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// [....]
//-----------------------------------------------------------------------------
namespace System.Data.ProviderBase {
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Data.Common;
using System.Threading;
#if ORACLE
using System.Data.OracleClient;
#endif
internal abstract class DbConnectionFactory {
private Dictionary _connectionPoolGroups;
private readonly List _poolsToRelease;
private readonly List _poolGroupsToRelease;
private readonly DbConnectionPoolCounters _performanceCounters;
private readonly Timer _pruningTimer;
private const int PruningDueTime =4*60*1000; // 4 minutes
private const int PruningPeriod = 30*1000; // thirty seconds
private static int _objectTypeCount; // Bid counter
internal readonly int _objectID = System.Threading.Interlocked.Increment(ref _objectTypeCount);
protected DbConnectionFactory() : this (DbConnectionPoolCountersNoCounters.SingletonInstance) { }
protected DbConnectionFactory(DbConnectionPoolCounters performanceCounters) {
_performanceCounters = performanceCounters;
_connectionPoolGroups = new Dictionary();
_poolsToRelease = new List();
_poolGroupsToRelease = new List();
_pruningTimer = CreatePruningTimer();
}
internal DbConnectionPoolCounters PerformanceCounters {
get { return _performanceCounters; }
}
abstract public DbProviderFactory ProviderFactory {
get;
}
internal int ObjectID {
get {
return _objectID;
}
}
public void ClearAllPools() {
IntPtr hscp;
Bid.ScopeEnter(out hscp, " ");
try {
Dictionary connectionPoolGroups = _connectionPoolGroups;
foreach (KeyValuePair entry in connectionPoolGroups) {
DbConnectionPoolGroup poolGroup = entry.Value;
if (null != poolGroup) {
Debug.Assert(!poolGroup.IsDisabled, "Disabled pool entry discovered");
poolGroup.Clear();
}
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
}
public void ClearPool(DbConnection connection) {
ADP.CheckArgumentNull(connection, "connection");
IntPtr hscp;
Bid.ScopeEnter(out hscp, " %d#" , GetObjectId(connection));
try {
DbConnectionPoolGroup poolGroup = GetConnectionPoolGroup(connection);
if (null != poolGroup) {
poolGroup.Clear();
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
}
#if !ORACLE
public void ClearPool(string connectionString) {
ADP.CheckArgumentNull(connectionString, "connectionString");
IntPtr hscp;
Bid.ScopeEnter(out hscp, " connectionString");
try {
DbConnectionPoolGroup poolGroup;
Dictionary connectionPoolGroups = _connectionPoolGroups;
if (connectionPoolGroups.TryGetValue(connectionString, out poolGroup)) {
poolGroup.Clear();
}
}
finally {
Bid.ScopeLeave(ref hscp);
}
}
#endif
internal virtual DbConnectionPoolProviderInfo CreateConnectionPoolProviderInfo(DbConnectionOptions connectionOptions){
return null;
}
virtual protected DbMetaDataFactory CreateMetaDataFactory(DbConnectionInternal internalConnection, out bool cacheMetaDataFactory) {
// providers that support GetSchema must override this with a method that creates a meta data
// factory appropriate for them.
cacheMetaDataFactory = false;
throw ADP.NotSupported();
}
internal DbConnectionInternal CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup) {
Debug.Assert(null != owningConnection, "null owningConnection?");
Debug.Assert(null != poolGroup, "null poolGroup?");
DbConnectionOptions connectionOptions = poolGroup.ConnectionOptions;
DbConnectionPoolGroupProviderInfo poolGroupProviderInfo = poolGroup.ProviderInfo;
DbConnectionInternal newConnection = CreateConnection(connectionOptions, poolGroupProviderInfo, null, owningConnection);
if (null != newConnection) {
PerformanceCounters.HardConnectsPerSecond.Increment();
newConnection.MakeNonPooledObject(owningConnection, PerformanceCounters);
}
Bid.Trace(" %d#, Non-pooled database connection created.\n", ObjectID);
return newConnection;
}
internal DbConnectionInternal CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) {
Debug.Assert(null != pool, "null pool?");
DbConnectionPoolGroupProviderInfo poolGroupProviderInfo = pool.PoolGroup.ProviderInfo;
DbConnectionInternal newConnection = CreateConnection(options, poolGroupProviderInfo, pool, owningConnection);
if (null != newConnection) {
PerformanceCounters.HardConnectsPerSecond.Increment();
newConnection.MakePooledConnection(pool);
}
Bid.Trace(" %d#, Pooled database connection created.\n", ObjectID);
return newConnection;
}
virtual internal DbConnectionPoolGroupProviderInfo CreateConnectionPoolGroupProviderInfo (DbConnectionOptions connectionOptions) {
return null;
}
private Timer CreatePruningTimer() {
TimerCallback callback = new TimerCallback(PruneConnectionPoolGroups);
return new Timer(callback, null, PruningDueTime, PruningPeriod);
}
#if !ORACLE
protected DbConnectionOptions FindConnectionOptions(string connectionString) {
if (!ADP.IsEmpty(connectionString)) {
DbConnectionPoolGroup connectionPoolGroup;
Dictionary connectionPoolGroups = _connectionPoolGroups;
if (connectionPoolGroups.TryGetValue(connectionString, out connectionPoolGroup)) {
return connectionPoolGroup.ConnectionOptions;
}
}
return null;
}
#endif
internal DbConnectionInternal GetConnection(DbConnection owningConnection) {
Debug.Assert(null != owningConnection, "null owningConnection?");
DbConnectionPoolGroup poolGroup;
DbConnectionPool connectionPool;
DbConnectionInternal connection;
// SQLBU 431251:
// Work around race condition with clearing the pool between GetConnectionPool obtaining pool
// and GetConnection on the pool checking the pool state. Clearing the pool in this window
// will switch the pool into the ShuttingDown state, and GetConnection will return null.
// There is probably a better solution involving locking the pool/group, but that entails a major
// re-design of the connection pooling synchronization, so is post-poned for now.
// use retriesLeft to prevent CPU spikes
int retriesLeft = 5;
do {
poolGroup = GetConnectionPoolGroup(owningConnection);
connectionPool = GetConnectionPool(owningConnection, poolGroup);
if (null == connectionPool) {
// If GetConnectionPool returns null, we can be certain that
// this connection should not be pooled via DbConnectionPool
// or have a disabled pool entry.
poolGroup = GetConnectionPoolGroup(owningConnection); // previous entry have been disabled
connection = CreateNonPooledConnection(owningConnection, poolGroup);
PerformanceCounters.NumberOfNonPooledConnections.Increment();
}
else {
connection = connectionPool.GetConnection(owningConnection);
if (connection != null) {
// we are done
break;
}
// connection creation failed on semaphore waiting or if max pool reached
if (connectionPool.IsRunning) {
// If GetConnection failed while the pool is running, the pool timeout occurred.
Bid.Trace(" %d#, GetConnection failed because a pool timeout occurred.\n", ObjectID);
throw ADP.PooledOpenTimeout();
}
else {
// We've hit the race condition, where the pool was shut down after we got it from the group.
// Yield time slice to allow shut down activities to complete and a new, running pool to be instantiated
// before retrying.
Threading.Thread.Sleep(1);
}
}
} while (connection == null && (retriesLeft--) > 0);
if (connection == null) {
// exhausted all retries or timed out - give up
Bid.Trace(" %d#, GetConnection failed because a pool timeout occurred and all retries were exhausted.\n", ObjectID);
throw ADP.PooledOpenTimeout();
}
return connection;
}
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)) {
Bid.Trace(" %d#, DisabledPoolGroup=%d#\n", ObjectID, connectionPoolGroup.ObjectID);
// 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;
string connectionString = connectionOptions.UsersConnectionString(false);
Debug.Assert(null != connectionOptions, "prevent expansion of connectionString");
connectionPoolGroup = GetConnectionPoolGroup(connectionString, poolOptions, ref connectionOptions);
Debug.Assert(null != connectionPoolGroup, "null connectionPoolGroup?");
SetConnectionPoolGroup(owningObject, connectionPoolGroup);
}
DbConnectionPool connectionPool = connectionPoolGroup.GetConnectionPool(this);
return connectionPool;
}
internal DbConnectionPoolGroup GetConnectionPoolGroup(string connectionString, DbConnectionPoolGroupOptions poolOptions, ref DbConnectionOptions userConnectionOptions) {
if (ADP.IsEmpty(connectionString)) {
return (DbConnectionPoolGroup)null;
}
DbConnectionPoolGroup connectionPoolGroup;
Dictionary connectionPoolGroups = _connectionPoolGroups;
if (!connectionPoolGroups.TryGetValue(connectionString, 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(connectionString, userConnectionOptions);
if (null == connectionOptions) {
throw ADP.InternalConnectionError(ADP.ConnectionError.ConnectionOptionsMissing);
}
string expandedConnectionString = connectionString;
if (null == userConnectionOptions) { // we only allow one expansion on the connection string
userConnectionOptions = connectionOptions;
expandedConnectionString = connectionOptions.Expand();
// if the expanded string is same instance (default implementation), the use the already created options
if ((object)expandedConnectionString != (object)connectionString) {
//
return GetConnectionPoolGroup(expandedConnectionString, null, ref userConnectionOptions);
}
}
// We don't support connection pooling on Win9x; it lacks too many of the APIs we require.
if ((null == poolOptions) && ADP.IsWindowsNT) {
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, poolOptions);
newConnectionPoolGroup.ProviderInfo = CreateConnectionPoolGroupProviderInfo(connectionOptions);
lock (this) {
connectionPoolGroups = _connectionPoolGroups;
if (!connectionPoolGroups.TryGetValue(expandedConnectionString, out connectionPoolGroup)) {
// build new dictionary with space for new connection string
Dictionary newConnectionPoolGroups = new Dictionary(1+connectionPoolGroups.Count);
foreach (KeyValuePair entry in connectionPoolGroups) {
newConnectionPoolGroups.Add(entry.Key, entry.Value);
}
// lock prevents race condition with PruneConnectionPoolGroups
newConnectionPoolGroups.Add(expandedConnectionString, newConnectionPoolGroup);
PerformanceCounters.NumberOfActiveConnectionPoolGroups.Increment();
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;
}
internal DbMetaDataFactory GetMetaDataFactory(DbConnectionPoolGroup connectionPoolGroup,DbConnectionInternal internalConnection){
Debug.Assert (connectionPoolGroup != null, "connectionPoolGroup may not be null.");
// get the matadatafactory from the pool entry. If it does not already have one
// create one and save it on the pool entry
DbMetaDataFactory metaDataFactory = connectionPoolGroup.MetaDataFactory;
// consider serializing this so we don't construct multiple metadata factories
// if two threads happen to hit this at the same time. One will be GC'd
if (metaDataFactory == null){
bool allowCache = false;
metaDataFactory = CreateMetaDataFactory(internalConnection, out allowCache);
if (allowCache) {
connectionPoolGroup.MetaDataFactory = metaDataFactory;
}
}
return metaDataFactory;
}
private void PruneConnectionPoolGroups(object state) {
// when debugging this method, expect multiple threads at the same time
if (Bid.AdvancedOn) {
Bid.Trace(" %d#\n", ObjectID);
}
// First, walk the pool release list and attempt to clear each
// pool, when the pool is finally empty, we dispose of it. If the
// pool isn't empty, it's because there are active connections or
// distributed transactions that need it.
lock (_poolsToRelease) {
if (0 != _poolsToRelease.Count) {
DbConnectionPool[] poolsToRelease = _poolsToRelease.ToArray();
foreach (DbConnectionPool pool in poolsToRelease) {
if (null != pool) {
pool.Clear();
if (0 == pool.Count) {
_poolsToRelease.Remove(pool);
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, ReleasePool=%d#\n", ObjectID, pool.ObjectID);
}
PerformanceCounters.NumberOfInactiveConnectionPools.Decrement();
}
}
}
}
}
// Next, walk the pool entry release list and dispose of each
// pool entry when it is finally empty. If the pool entry isn't
// empty, it's because there are active pools that need it.
lock (_poolGroupsToRelease) {
if (0 != _poolGroupsToRelease.Count) {
DbConnectionPoolGroup[] poolGroupsToRelease = _poolGroupsToRelease.ToArray();
foreach (DbConnectionPoolGroup poolGroup in poolGroupsToRelease) {
if (null != poolGroup) {
poolGroup.Clear(); // may add entries to _poolsToRelease
if (0 == poolGroup.Count) {
_poolGroupsToRelease.Remove(poolGroup);
if (Bid.AdvancedOn) {
Bid.Trace(" %d#, ReleasePoolGroup=%d#\n", ObjectID, poolGroup.ObjectID);
}
PerformanceCounters.NumberOfInactiveConnectionPoolGroups.Decrement();
}
}
}
}
}
// Finally, we walk through the collection of connection pool entries
// and prune each one. This will cause any empty pools to be put
// into the release list.
lock (this) {
Dictionary connectionPoolGroups = _connectionPoolGroups;
Dictionary newConnectionPoolGroups = new Dictionary(connectionPoolGroups.Count);
foreach (KeyValuePair entry in connectionPoolGroups) {
if (null != entry.Value) {
Debug.Assert(!entry.Value.IsDisabled, "Disabled pool entry discovered");
// entries start active and go idle during prune if all pools are gone
// move idle entries from last prune pass to a queue for pending release
// otherwise process entry which may move it from active to idle
if (entry.Value.Prune()) { // may add entries to _poolsToRelease
PerformanceCounters.NumberOfActiveConnectionPoolGroups.Decrement();
QueuePoolGroupForRelease(entry.Value);
}
else {
newConnectionPoolGroups.Add(entry.Key, entry.Value);
}
}
}
_connectionPoolGroups = newConnectionPoolGroups;
}
}
internal void QueuePoolForRelease(DbConnectionPool pool, bool clearing) {
// Queue the pool up for release -- we'll clear it out and dispose
// of it as the last part of the pruning timer callback so we don't
// do it with the pool entry or the pool collection locked.
Debug.Assert (null != pool, "null pool?");
// set the pool to the shutdown state to force all active
// connections to be automatically disposed when they
// are returned to the pool
pool.Shutdown();
lock (_poolsToRelease) {
if (clearing) {
pool.Clear();
}
_poolsToRelease.Add(pool);
}
PerformanceCounters.NumberOfInactiveConnectionPools.Increment();
}
internal void QueuePoolGroupForRelease(DbConnectionPoolGroup poolGroup) {
Debug.Assert (null != poolGroup, "null poolGroup?");
Bid.Trace(" %d#, poolGroup=%d#\n", ObjectID, poolGroup.ObjectID);
lock (_poolGroupsToRelease) {
_poolGroupsToRelease.Add(poolGroup);
}
PerformanceCounters.NumberOfInactiveConnectionPoolGroups.Increment();
}
abstract protected DbConnectionInternal CreateConnection(DbConnectionOptions options, object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection);
abstract protected DbConnectionOptions CreateConnectionOptions(string connectionString, DbConnectionOptions previous);
abstract protected DbConnectionPoolGroupOptions CreateConnectionPoolGroupOptions(DbConnectionOptions options);
abstract internal DbConnectionPoolGroup GetConnectionPoolGroup(DbConnection connection);
abstract internal DbConnectionInternal GetInnerConnection(DbConnection connection);
abstract protected int GetObjectId(DbConnection connection);
abstract internal void PermissionDemand(DbConnection outerConnection);
abstract internal void SetConnectionPoolGroup(DbConnection outerConnection, DbConnectionPoolGroup poolGroup);
abstract internal void SetInnerConnectionEvent(DbConnection owningObject, DbConnectionInternal to);
abstract internal bool SetInnerConnectionFrom(DbConnection owningObject, DbConnectionInternal to, DbConnectionInternal from) ;
abstract internal void SetInnerConnectionTo(DbConnection owningObject, DbConnectionInternal to);
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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