public void Return(MySqlSession session)
{
try
{
if (session.PoolGeneration == m_generation)
{
m_sessions.Enqueue(session);
}
else
{
session.DisposeAsync(IOBehavior.Synchronous, CancellationToken.None).ConfigureAwait(false);
}
}
finally
{
m_session_semaphore.Release();
}
}
public void Return(MySqlSession session)
{
try
{
lock (m_leasedSessions)
m_leasedSessions.Remove(session.Id);
if (SessionIsHealthy(session))
{
lock (m_sessions)
m_sessions.AddFirst(session);
}
else
{
session.DisposeAsync(IOBehavior.Synchronous, CancellationToken.None).ConfigureAwait(false);
}
}
finally
{
m_sessionSemaphore.Release();
}
}
private async Task CleanPoolAsync(IOBehavior ioBehavior, Func <MySqlSession, bool> shouldCleanFn, bool respectMinPoolSize, CancellationToken cancellationToken)
{
// synchronize access to this method as only one clean routine should be run at a time
if (ioBehavior == IOBehavior.Asynchronous)
{
await m_cleanSemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
}
else
{
m_cleanSemaphore.Wait(cancellationToken);
}
try
{
var waitTimeout = TimeSpan.FromMilliseconds(10);
while (true)
{
// if respectMinPoolSize is true, return if (leased sessions + waiting sessions <= minPoolSize)
if (respectMinPoolSize)
{
lock (m_sessions)
if (m_connectionSettings.MaximumPoolSize - m_sessionSemaphore.CurrentCount + m_sessions.Count <= m_connectionSettings.MinimumPoolSize)
{
return;
}
}
// try to get an open slot; if this fails, connection pool is full and sessions will be disposed when returned to pool
if (ioBehavior == IOBehavior.Asynchronous)
{
if (!await m_sessionSemaphore.WaitAsync(waitTimeout, cancellationToken).ConfigureAwait(false))
{
return;
}
}
else
{
if (!m_sessionSemaphore.Wait(waitTimeout, cancellationToken))
{
return;
}
}
try
{
// check for a waiting session
MySqlSession session = null;
lock (m_sessions)
{
if (m_sessions.Count > 0)
{
session = m_sessions.Last.Value;
m_sessions.RemoveLast();
}
}
if (session == null)
{
return;
}
if (shouldCleanFn(session))
{
// session should be cleaned; dispose it and keep iterating
await session.DisposeAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
}
else
{
// session should not be cleaned; put it back in the queue and stop iterating
lock (m_sessions)
m_sessions.AddLast(session);
return;
}
}
finally
{
m_sessionSemaphore.Release();
}
}
}
finally
{
m_cleanSemaphore.Release();
}
}
public async Task <MySqlSession> GetSessionAsync(MySqlConnection connection, IOBehavior ioBehavior, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
// if all sessions are used, see if any have been leaked and can be recovered
// check at most once per second (although this isn't enforced via a mutex so multiple threads might block
// on the lock in RecoverLeakedSessions in high-concurrency situations
if (m_sessionSemaphore.CurrentCount == 0 && unchecked (((uint)Environment.TickCount) - m_lastRecoveryTime) >= 1000u)
{
RecoverLeakedSessions();
}
// wait for an open slot (until the cancellationToken is cancelled, which is typically due to timeout)
if (ioBehavior == IOBehavior.Asynchronous)
{
await m_sessionSemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
}
else
{
m_sessionSemaphore.Wait(cancellationToken);
}
try
{
// check for a waiting session
MySqlSession session = null;
lock (m_sessions)
{
if (m_sessions.Count > 0)
{
session = m_sessions.First.Value;
m_sessions.RemoveFirst();
}
}
if (session != null)
{
bool reuseSession;
if (session.PoolGeneration != m_generation)
{
reuseSession = false;
}
else
{
if (m_connectionSettings.ConnectionReset)
{
reuseSession = await session.TryResetConnectionAsync(m_connectionSettings, ioBehavior, cancellationToken).ConfigureAwait(false);
}
else
{
reuseSession = await session.TryPingAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
}
}
if (!reuseSession)
{
// session is either old or cannot communicate with the server
await session.DisposeAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
}
else
{
// pooled session is ready to be used; return it
session.OwningConnection = new WeakReference <MySqlConnection>(connection);
lock (m_leasedSessions)
m_leasedSessions.Add(session.Id, session);
return(session);
}
}
// create a new session
session = new MySqlSession(this, m_generation, Interlocked.Increment(ref m_lastId));
await session.ConnectAsync(m_connectionSettings, ioBehavior, cancellationToken).ConfigureAwait(false);
session.OwningConnection = new WeakReference <MySqlConnection>(connection);
lock (m_leasedSessions)
m_leasedSessions.Add(session.Id, session);
return(session);
}
catch
{
m_sessionSemaphore.Release();
throw;
}
}
