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[6.1] Cleanup semaphore holder #3664

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Merged
merged 2 commits into from
Oct 7, 2025
Merged

[6.1] Cleanup semaphore holder #3664

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aabb906
Cleanup semaphore holder
cheenamalhotra Oct 6, 2025
c744b4d
Minor change (fix cer)
cheenamalhotra Oct 6, 2025
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86 changes: 32 additions & 54 deletions ....Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/WaitHandleDbConnectionPool.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -382,42 +382,6 @@ internal WaitHandle[] GetHandles(bool withCreate)
return withCreate ? _handlesWithCreate : _handlesWithoutCreate;
}
}

/// <summary>
/// Helper class to obtain and release a semaphore.
/// </summary>
internal class SemaphoreHolder : IDisposable
{
private readonly Semaphore _semaphore;

/// <summary>
/// Whether the semaphore was successfully obtained within the timeout.
/// </summary>
internal bool Obtained { get; private set; }

/// <summary>
/// Obtains the semaphore, waiting up to the specified timeout.
/// </summary>
/// <param name="semaphore"></param>
/// <param name="timeout"></param>
internal SemaphoreHolder(Semaphore semaphore, int timeout)
{
_semaphore = semaphore;
Obtained = _semaphore.WaitOne(timeout);
}

/// <summary>
/// Releases the semaphore if it was successfully obtained.
/// </summary>
public void Dispose()
{
if (Obtained)
{
_semaphore.Release(1);
}
}
}

private const int MAX_Q_SIZE = 0x00100000;

// The order of these is important; we want the WaitAny call to be signaled
Expand Down Expand Up @@ -1356,26 +1320,36 @@ private bool TryGetConnection(DbConnection owningObject, uint waitForMultipleObj

if (onlyOneCheckConnection)
{
using SemaphoreHolder semaphoreHolder = new(_waitHandles.CreationSemaphore, unchecked((int)waitForMultipleObjectsTimeout));
if (semaphoreHolder.Obtained)
{
bool obtained = false;
#if NETFRAMEWORK
RuntimeHelpers.PrepareConstrainedRegions();
RuntimeHelpers.PrepareConstrainedRegions();
#endif
SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.GetConnection|RES|CPOOL> {0}, Creating new connection.", Id);
obj = UserCreateRequest(owningObject, userOptions);
try
{
obtained = _waitHandles.CreationSemaphore.WaitOne(unchecked((int)waitForMultipleObjectsTimeout));
if (obtained)
{
SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.GetConnection|RES|CPOOL> {0}, Creating new connection.", Id);
obj = UserCreateRequest(owningObject, userOptions);
}
else
{
// Timeout waiting for creation semaphore - return null
SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.GetConnection|RES|CPOOL> {0}, Wait timed out.", Id);
connection = null;
return false;
}
}
else
finally
{
// Timeout waiting for creation semaphore - return null
SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.GetConnection|RES|CPOOL> {0}, Wait timed out.", Id);
connection = null;
return false;
if (obtained)
{
_waitHandles.CreationSemaphore.Release(1);
}
}
}
}
break;

case WAIT_ABANDONED + SEMAPHORE_HANDLE:
SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.GetConnection|RES|CPOOL> {0}, Semaphore handle abandonded.", Id);
Interlocked.Decrement(ref _waitCount);
Expand Down Expand Up @@ -1582,20 +1556,17 @@ private void PoolCreateRequest(object state)
{
return;
}

#if NETFRAMEWORK
RuntimeHelpers.PrepareConstrainedRegions();
#endif
bool obtained = false;
try
{
// Obtain creation mutex so we're the only one creating objects
using SemaphoreHolder semaphoreHolder = new(_waitHandles.CreationSemaphore, CreationTimeout);
obtained = _waitHandles.CreationSemaphore.WaitOne(CreationTimeout);

if (semaphoreHolder.Obtained)
if (obtained)
{
#if NETFRAMEWORK
RuntimeHelpers.PrepareConstrainedRegions();
#endif
DbConnectionInternal newObj;

// Check ErrorOccurred again after obtaining mutex
Expand Down Expand Up @@ -1648,6 +1619,13 @@ private void PoolCreateRequest(object state)
// thrown to the user the next time they request a connection.
SqlClientEventSource.Log.TryPoolerTraceEvent("<prov.DbConnectionPool.PoolCreateRequest|RES|CPOOL> {0}, PoolCreateRequest called CreateConnection which threw an exception: {1}", Id, e);
}
finally
{
if (obtained)
{
_waitHandles.CreationSemaphore.Release(1);
}
}
}
}
}
Expand Down
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