A potential optimization point for the buffer::save and persistence

[Unalian]

Why tmp_file is needed before persistence? I don't see any reason to use the tmp files, which seems like a redundant step.

If we write the data from BufferObj.file_worked_ into memory and then persist them directly without tmp_file, we can reduce the reading and writing from tmp files to obj.

infinity/src/storage/buffer/file_worker/file_worker.cpp

Lines 43 to 73 in 861c142

	bool FileWorker::WriteToFile(bool to_spill, const FileWorkerSaveCtx &ctx) {
	if (data_ == nullptr) {
	String error_message = "No data will be written.";
	UnrecoverableError(error_message);
	}
	if(persistence_manager_ != nullptr && !to_spill) {
	String write_dir = *file_dir_;
	String write_path = Path(*data_dir_) / write_dir / *file_name_;
	String tmp_write_path = Path(*temp_dir_) / StringTransform(write_path, "/", "_");
	auto [file_handle, status] = VirtualStore::Open(tmp_write_path, FileAccessMode::kWrite);
	if (!status.ok()) {
	UnrecoverableError(status.message());
	}
	file_handle_ = std::move(file_handle);
	DeferFn defer_fn([&]() {
	file_handle_ = nullptr;
	});
	bool prepare_success = false;
	bool all_save = WriteToFileImpl(to_spill, prepare_success, ctx);
	if (prepare_success) {
	file_handle_->Sync();
	}
	file_handle_->Sync();
	PersistResultHandler handler(persistence_manager_);
	PersistWriteResult persist_result = persistence_manager_->Persist(write_path, tmp_write_path);

[small-turtle-1]

Tmp file is for simplicity and is a temporary solution. By using tmp file, we can reuse some old code. It does cause redundent write and read from disk.