private DBPooledObject TryGetResourceFromContext(out bool isInTransaction)
{
isInTransaction = false;
DBPooledObject obj = null;
try {
if (PoolControl.TransactionAffinity && ContextUtil.IsInTransaction)
{
isInTransaction = true;
if (null != _txPool)
{
obj = (DBPooledObject)_txPool.GetResource();
}
}
else
{
isInTransaction = false;
}
}
catch (Exception e) {
ADP.TraceException(e);
}
#if ALLOWTRACING
if (null != obj)
{
ADP.TraceObjectPoolActivity("GetFromTransactedPool", obj);
}
#endif //ALLOWTRACING
return(obj);
}
static internal void TraceObjectPoolActivity(string eventName, DBPooledObject pooledObject)
{
if (_traceObjectPoolActivity)
{
Debug.WriteLine(String.Format("*** {0,-24} svcctx=0x{1}",
eventName,
((IntPtr)((OracleInternalConnection)pooledObject).ServiceContextHandle.Handle).ToInt64().ToString("x")
));
}
}
private void PutNewObject(DBPooledObject obj)
{
Debug.Assert(null != obj, "why are we adding a null object to the pool?");
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("PutToGeneralPool", obj);
#endif //ALLOWTRACING
_stackNew.Push(obj);
#if USECOUNTEROBJECT
_poolCounter.Modify(cAddFree);
#endif //USECOUNTEROBJECT
SafeNativeMethods.ReleaseSemaphore(_waitHandles[SEMAPHORE_HANDLE].Handle, 1, IntPtr.Zero);
}
private void DestroyObject(DBPooledObject obj)
{
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("DestroyObject", obj);
#endif //ALLOWTRACING
lock (_objectList.SyncRoot) {
_objectList.Remove(obj);
#if !USECOUNTEROBJECT
_totalObjects = _objectList.Count;
#endif //!USECOUNTEROBJECT
}
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddTotal);
#endif //USECOUNTEROBJECT
PoolControl.DestroyObject(this, obj);
}
private DBPooledObject CreateObject()
{
DBPooledObject newObj = null;
try {
newObj = PoolControl.CreateObject(this);
Debug.Assert(newObj != null, "CreateObject succeeded, but object null");
newObj.PrePush(null);
lock (_objectList.SyncRoot) {
_objectList.Add(newObj);
#if !USECOUNTEROBJECT
_totalObjects = _objectList.Count;
#endif //!USECOUNTEROBJECT
}
#if USECOUNTEROBJECT
_poolCounter.Modify(cAddTotal);
#endif //USECOUNTEROBJECT
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("CreateObject", newObj);
#endif //ALLOWTRACING
// Reset the error wait:
_errorWait = ERROR_WAIT_DEFAULT;
}
catch (Exception e) {
ADP.TraceException(e);
newObj = null; // set to null, so we do not return bad new object
// Failed to create instance
_resError = e;
SafeNativeMethods.SetEvent(_waitHandles[ERROR_HANDLE].Handle);
#if USECOUNTEROBJECT
_poolCounter.Modify(cErrorFlag);
#else //!USECOUNTEROBJECT
_errorOccurred = true;
#endif //!USECOUNTEROBJECT
_errorTimer = new Timer(new TimerCallback(this.ErrorCallback), null, _errorWait, _errorWait);
_errorWait *= 2;
}
return(newObj);
}
private void ReturnToPool()
{
if (_signaled)
{
if (null != _pooledObject && null != _pool)
{
_pool.PutNewObject(_pooledObject);
_pool = null;
_pooledObject = null;
}
if (0 != _cookie && null != _point)
{
_point.Unadvise(_cookie);
_point = null;
_cookie = 0;
}
}
}
private bool TryPutResourceInContext(DBPooledObject obj)
{
try {
if (PoolControl.TransactionAffinity && ContextUtil.IsInTransaction)
{
if (null != _txPool)
{
if (_txPool.PutResource(obj))
{
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("PutToTransactedPool", obj);
#endif //ALLOWTRACING
return(true);
}
}
}
}
catch (Exception e) {
ADP.TraceException(e);
}
return(false);
}
private DBPooledObject GetFromPool(object owningObject)
{
DBPooledObject res = null;
res = (DBPooledObject)_stackNew.Pop();
if (res == null)
{
res = (DBPooledObject)_stackOld.Pop();
}
// Shouldn't be null, we could assert here.
Debug.Assert(res != null, "GetFromPool called with nothing in the pool!");
if (null != res)
{
res.PostPop(owningObject);
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("GetFromGeneralPool", res);
#endif //ALLOWTRACING
}
return(res);
}
public void PutObject(DBPooledObject obj, object owningObject)
{
if (obj == null)
{
throw ADP.ArgumentNull("obj");
}
obj.PrePush(owningObject);
if (_state != State.ShuttingDown)
{
bool isInTransaction = obj.Deactivate();
if (obj.CanBePooled())
{
#if USEORAMTS
ITransaction transaction = obj.ManualEnlistedTransaction;
if (null != transaction)
{
// When the object is put back into the pool while it is manually
// enlisted in a distributed transaction, we must create an outcome
// event and let the object wait until the distributed transaction
// has finished. Once it does, the TransactionOutcomeEvents class
// can put it back into the general population of the pool.
UCOMIConnectionPoint point = (UCOMIConnectionPoint)transaction;
TransactionOutcomeEvents outcomeEvent = new TransactionOutcomeEvents(this, obj, point);
Int32 cookie = 0;
point.Advise(outcomeEvent, out cookie); // Register for callbacks, obtain cookie
outcomeEvent.SetCookie(cookie); // Set the cookie on the event
#if ALLOWTRACING
ADP.TraceObjectPoolActivity("WaitForOutcomeEvnt", obj);
#endif //ALLOWTRACING
return;
}
#endif //USEORAMTS
// Try shoving it in the tx context first. If that succeeds,
// we're done.
if (isInTransaction && TryPutResourceInContext(obj))
{
return;
}
// If the above failed, we just shove it into our current collection
PutNewObject(obj);
}
else
{
DestroyObject(obj);
// Make sure we're at quota by posting a callback to the threadpool.
ThreadPool.QueueUserWorkItem(new WaitCallback(PoolCreateRequest));
}
}
else
{
// If we're shutting down, we destroy the object.
DestroyObject(obj);
}
}
public DBPooledObject GetObject(object owningObject, out bool isInTransaction)
{
DBPooledObject obj = null;
isInTransaction = false;
if (_state != State.Running)
{
return(null);
}
// Try to get from the context if we're context specific:
obj = TryGetResourceFromContext(out isInTransaction);
if (null != obj)
{
obj.PostPop(owningObject);
}
else
{
#if USECOUNTEROBJECT
_poolCounter.Modify(cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Increment(ref _waitCount);
#endif //!USECOUNTEROBJECT
ObjectPoolWaitHandle[] localWaitHandles = _waitHandles;
while (obj == null)
{
int r = WaitHandle.WaitAny(localWaitHandles, PoolControl.CreationTimeout, false);
// From the WaitAny docs: "If more than one object became signaled during
// the call, this is the array index of the signaled object with the
// smallest index value of all the signaled objects." This is important
// so that the free object signal will be returned before a creation
// signal.
switch (r)
{
case WAIT_TIMEOUT:
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
return(null);
case ERROR_HANDLE:
// Throw the error that PoolCreateRequest stashed.
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
throw _resError;
case CREATION_HANDLE:
try {
obj = UserCreateRequest();
if (null != obj)
{
obj.PostPop(owningObject);
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
}
else
{
// If we were not able to create an object, check to see if
// we reached MaxPool. If so, we will no longer wait on the
// CreationHandle, but instead wait for a free object or
// the timeout.
// BUG - if we receive the CreationHandle midway into the wait
// period and re-wait, we will be waiting on the full period
#if USECOUNTEROBJECT
if (_poolCounter.TotalCount == PoolControl.MaxPool)
{
#else //!USECOUNTEROBJECT
if (Count >= PoolControl.MaxPool)
{
#endif //!USECOUNTEROBJECT
if (!ReclaimEmancipatedObjects())
{
// modify handle array not to wait on creation mutex anymore
localWaitHandles = new ObjectPoolWaitHandle[2];
localWaitHandles[0] = _waitHandles[0];
localWaitHandles[1] = _waitHandles[1];
}
}
}
}
finally {
_creationMutex.ReleaseMutex();
}
break;
default:
//
// guaranteed available inventory
//
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddWait - cAddFree);
#else //!USECOUNTEROBJECT
Interlocked.Decrement(ref _waitCount);
#endif //!USECOUNTEROBJECT
obj = GetFromPool(owningObject);
break;
}
}
}
Debug.Assert(obj != null, "Failed to create pooled object, resulted in null instance.");
if (null != obj)
{
obj.Activate();
}
return(obj);
}
private void CleanupCallback(Object state)
{
// Called when the cleanup-timer ticks over.
//
// This is the automatic prunning method. Every period, we will perform a two-step
// process. First, for the objects above MinPool, we will obtain the semaphore for
// the object and then destroy it if it was on the old stack. We will continue this
// until we either reach MinPool size, or we are unable to obtain a free object, or
// until we have exhausted all the objects on the old stack. After that, push all
// objects on the new stack to the old stack. So, every period the objects on the
// old stack are destroyed and the objects on the new stack are pushed to the old
// stack. All objects that are currently out and in use are not on either stack.
// With this logic, a object is prunned if unused for at least one period but not
// more than two periods.
// Destroy free objects above MinPool size from old stack.
#if USECOUNTEROBJECT
while (_poolCounter.TotalCount > _ctrl.MinPool)
#else //!USECOUNTEROBJECT
while (Count > _ctrl.MinPool)
#endif //!USECOUNTEROBJECT
{
// While above MinPoolSize...
if (_waitHandles[SEMAPHORE_HANDLE].WaitOne(0, false) /* != WAIT_TIMEOUT */)
{
// We obtained a objects from the semaphore.
DBPooledObject obj = (DBPooledObject)_stackOld.Pop();
if (null != obj)
{
// If we obtained one from the old stack, destroy it.
#if USECOUNTEROBJECT
_poolCounter.Modify(-cAddFree);
#endif //USECOUNTEROBJECT
DestroyObject(obj);
}
else
{
// Else we exhausted the old stack, so break.
SafeNativeMethods.ReleaseSemaphore(_waitHandles[SEMAPHORE_HANDLE].Handle, 1, IntPtr.Zero);
break;
}
}
else
{
break;
}
}
// Push to the old-stack. For each free object, move object from new stack
// to old stack.
if (_waitHandles[SEMAPHORE_HANDLE].WaitOne(0, false) /* != WAIT_TIMEOUT */)
{
for (;;)
{
DBPooledObject obj = (DBPooledObject)_stackNew.Pop();
if (null == obj)
{
break;
}
_stackOld.Push(obj);
}
SafeNativeMethods.ReleaseSemaphore(_waitHandles[SEMAPHORE_HANDLE].Handle, 1, IntPtr.Zero);
}
// Make sure we're at quota by posting a callback to the threadpool.
ThreadPool.QueueUserWorkItem(new WaitCallback(PoolCreateRequest));
}
private bool _signaled; // Bool in case signal occurs before Cookie is set.
public TransactionOutcomeEvents(DBObjectPool pool, DBPooledObject pooledObject, UCOMIConnectionPoint point)
{
_pool = pool;
_pooledObject = pooledObject;
_point = point;
}
public abstract void DestroyObject(DBObjectPool p, DBPooledObject con);
public override void DestroyObject(DBObjectPool p, DBPooledObject con)
{
con.Close();
}
