yiguolei commented on code in PR #48924: URL: https://github.com/apache/doris/pull/48924#discussion_r1988859663
########## be/src/olap/segment_footer_cache.h: ########## @@ -0,0 +1,115 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#pragma once + +#include <gen_cpp/segment_v2.pb.h> + +#include <memory> + +#include "common/logging.h" +#include "common/status.h" +#include "olap/metadata_adder.h" +#include "olap/page_cache.h" +#include "runtime/exec_env.h" +#include "runtime/memory/lru_cache_policy.h" +#include "util/once.h" +#include "vec/common/allocator.h" +#include "vec/common/allocator_fwd.h" + +namespace doris { +/* +template <typename TAllocator> +class PageBase : private TAllocator, public LRUCacheValueBase { +public: + PageBase() = default; + PageBase(size_t b, bool use_cache, segment_v2::PageTypePB page_type); + PageBase(const PageBase&) = delete; + PageBase& operator=(const PageBase&) = delete; + ~PageBase() override; + + char* data() { return _data; } + size_t size() { return _size; } + size_t capacity() { return _capacity; } + + void reset_size(size_t n) { + DCHECK(n <= _capacity); + _size = n; + } + +private: + char* _data = nullptr; + // Effective size, smaller than capacity, such as data page remove checksum suffix. + size_t _size = 0; + size_t _capacity = 0; + std::shared_ptr<MemTrackerLimiter> _mem_tracker_by_allocator; +}; +*/ + +class SegmentFooterDataPage : public PageBase<Allocator<false>> { + // Need to implement some virtual methods. +public: + using LoadFooterFn = std::function<Status(std::shared_ptr<segment_v2::SegmentFooterPB>)>; + + explicit SegmentFooterDataPage(LoadFooterFn load_function) : _load_function(load_function) {} + + std::shared_ptr<segment_v2::SegmentFooterPB> load_once() { + return _load_once.call([this]() { return this->_load_and_update(); }); + } + +private: + DorisCallOnce<std::shared_ptr<segment_v2::SegmentFooterPB>> _load_once; + LoadFooterFn _load_function; + + std::shared_ptr<segment_v2::SegmentFooterPB> _load_and_update() { + std::shared_ptr<segment_v2::SegmentFooterPB> footer = + std::make_shared<segment_v2::SegmentFooterPB>(); + Status load_status = _load_function(footer); Review Comment: 这个并发控制逻辑移动到segment 类中，因为那里本来就要处理file reader 读取footer 文件的并发问题，现在你把loadonce 带lock，然后load function 还要带lock，因为他不能假定底层你带lock了，所以不小心就会死锁。 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
