internal int Clear()
{
// must be multi-thread safe with competing calls by Clear and Prune via background thread
// will return the number of connections in the group after clearing has finished
// First, note the old collection and create a new collection to be used
ConcurrentDictionary <DbConnectionPoolIdentity, DbConnectionPool> oldPoolCollection = null;
lock (this)
{
if (_poolCollection.Count > 0)
{
oldPoolCollection = _poolCollection;
_poolCollection = new ConcurrentDictionary <DbConnectionPoolIdentity, DbConnectionPool>();
}
}
// Then, if a new collection was created, release the pools from the old collection
if (oldPoolCollection != null)
{
foreach (var entry in oldPoolCollection)
{
DbConnectionPool pool = entry.Value;
if (pool != null)
{
DbConnectionFactory connectionFactory = pool.ConnectionFactory;
connectionFactory.QueuePoolForRelease(pool, true);
}
}
}
// Finally, return the pool collection count - this may be non-zero if something was added while we were clearing
return(_poolCollection.Count);
}
internal bool Prune()
{
// must only call from DbConnectionFactory.PruneConnectionPoolGroups on background timer thread
// must lock(DbConnectionFactory._connectionPoolGroups.SyncRoot) before calling ReadyToRemove
// to avoid conflict with DbConnectionFactory.CreateConnectionPoolGroup replacing pool entry
lock (this)
{
if (_poolCollection.Count > 0)
{
var newPoolCollection = new ConcurrentDictionary <DbConnectionPoolIdentity, DbConnectionPool>();
foreach (var entry in _poolCollection)
{
DbConnectionPool pool = entry.Value;
if (pool != null)
{
// Actually prune the pool if there are no connections in the pool and no errors occurred.
// Empty pool during pruning indicates zero or low activity, but
// an error state indicates the pool needs to stay around to
// throttle new connection attempts.
if ((!pool.ErrorOccurred) && (0 == pool.Count))
{
// Order is important here. First we remove the pool
// from the collection of pools so no one will try
// to use it while we're processing and finally we put the
// pool into a list of pools to be released when they
// are completely empty.
DbConnectionFactory connectionFactory = pool.ConnectionFactory;
connectionFactory.QueuePoolForRelease(pool, false);
}
else
{
newPoolCollection.TryAdd(entry.Key, entry.Value);
}
}
}
_poolCollection = newPoolCollection;
}
// must be pruning thread to change state and no connections
// otherwise pruning thread risks making entry disabled soon after user calls ClearPool
if (0 == _poolCollection.Count)
{
if (PoolGroupStateActive == _state)
{
_state = PoolGroupStateIdle;
}
else if (PoolGroupStateIdle == _state)
{
_state = PoolGroupStateDisabled;
}
}
return(PoolGroupStateDisabled == _state);
}
}