message: Correctly lock all clients during checkpoint
diff: @@ -136,6 +136,10 @@ string TransactionManager::CommitTransaction(ClientContext &context, Transaction
  LockClients(client_locks, context);
  lock = make_unique<lock_guard<mutex>>(transaction_lock);
  + can_checkpoint = CanCheckpoint();
  + if (!can_checkpoint) {
  + client_locks.clear();
  + }
  }
  // obtain a commit id for the transaction
  transaction_t commit_id = current_start_timestamp++;
  @@ -158,7 +162,6 @@ string TransactionManager::CommitTransaction(ClientContext &context, Transaction
  // now perform a checkpoint if (1) we are able to checkpoint, and (2) the WAL has reached sufficient size to checkpoint
  if (can_checkpoint) {
  // checkpoint the database to disk
  - // FIXME: lock all clients
  auto &storage_manager = StorageManager::GetStorageManager(db);
  storage_manager.CreateCheckpoint(false, true);
  }
  