message: Purge concurrent queue when enqueueing entries to prevent entries from piling up
diff: @@ -302,8 +302,8 @@ unique_ptr<BufferHandle> BufferManager::Pin(shared_ptr<BlockHandle> &handle) {
  void BufferManager::AddToEvictionQueue(shared_ptr<BlockHandle> &handle) {
  D_ASSERT(handle->readers == 0);
  handle->eviction_timestamp++;
  + PurgeQueue();
  queue->q.enqueue(make_unique<BufferEvictionNode>(weak_ptr<BlockHandle>(handle), handle->eviction_timestamp));
  - // FIXME: do some house-keeping to prevent the queue from being flooded with many old blocks
  }
  void BufferManager::Unpin(shared_ptr<BlockHandle> &handle) {
  