CMU15445 LAB1 BUFFER POOL

2020fall lab1

实验说明

• 该lab需要实现一个buffer pool
• lab的实现需要是线程安全的，用latch(在os中被称作lock)来保护内部数据结构的关键部分
• 任务1 LRU替换策略
  • 主要是实现LRUReplacer这个子类
  • LRUReplacer的大小与BufferPool一致，但是只有unpinned的frame才会放到LRUReplacer之中
  • 需要实现Victim(T*),Pin(T),Unpin(T),Size()这几个方法
• 任务2 BUFFER POOL MANAGER
  • BufferPoolManager的主要功能是在磁盘与内存读写database的数据 ，DiskManager以及实现了
  • BufferPoolManager将会将数据读写在Page对象中
  • Page对象会记录dirty flag与pin reference以及它现在存有的物理页的page_id
  • 需要实现的函数有
  • Buffer Pool是有一个free list的，如果没有空闲的Page了，那就返回NULL
  • FlushPageImpl需要直接flush一个Page对象，不论其pin的状态

测试

记得去掉测试中的DISABLED_

$ mkdir build
$ cd build
$ make lru_replacer_test
$ ./test/lru_replacer_test

// 测试全部
make check-tests

gradescope打分

// 每次在bash中输入这打包提交
zip project1.zip  src/include/buffer/lru_replacer.h  src/buffer/lru_replacer.cpp src/include/buffer/buffer_pool_manager.h  src/buffer/buffer_pool_manager.cpp

# 别人写的bash，侵删
#!/usr/bin/env bash

print_help() {
    echo -e "Usage:\n"
    echo -e "  $ archive_submission proj#\n"
    echo -e "Example:\n"
    echo -e "  $ archive_submission 0\n"
    echo -e "This will archive project 0. Choices:\n"
    echo -e "  0 - C++ Primer"
    echo -e "  1 - Buffer Pool Manager"
    echo -e "  2 - B+ Tree Index"
    echo -e "  3 - Query Execution"
    echo -e "  4 - Concurrency Control"
}

out="proj$1-submission"
if [[ -f ./$out.zip ]]; then
    rm $out.zip
fi

case $1 in
  4)
    zip $out -urq \
    src/concurrency/lock_manager.cpp \
    src/include/concurrency/lock_manager.h
  ;;
  3)
    zip $out -urq \
    src/include/catalog/catalog.h \
    src/include/execution/execution_engine.h \
    src/include/execution/executor_factory.h \
    src/include/execution/executors/seq_scan_executor.h \
    src/include/execution/executors/index_scan_executor.h \
    src/include/execution/executors/insert_executor.h \
    src/include/execution/executors/update_executor.h \
    src/include/execution/executors/delete_executor.h \
    src/include/execution/executors/nested_loop_join_executor.h \
    src/include/execution/executors/nested_index_join_executor.h \
    src/include/execution/executors/limit_executor.h \
    src/include/execution/executors/aggregation_executor.h \
    src/include/storage/index/b_plus_tree_index.h \
    src/include/storage/index/index.h \
    src/execution/executor_factory.cpp \
    src/execution/seq_scan_executor.cpp \
    src/execution/index_scan_executor.cpp \
    src/execution/insert_executor.cpp \
    src/execution/update_executor.cpp \
    src/execution/delete_executor.cpp \
    src/execution/nested_loop_join_executor.cpp \
    src/execution/nested_index_join_executor.cpp \
    src/execution/limit_executor.cpp \
    src/execution/aggregation_executor.cpp \
    src/storage/index/b_plus_tree_index.cpp
  ;;
  2)
    zip $out -urq \
    src/include/storage/page/b_plus_tree_page.h \
    src/storage/page/b_plus_tree_page.cpp \
    src/include/storage/page/b_plus_tree_internal_page.h \
    src/storage/page/b_plus_tree_internal_page.cpp \
    src/include/storage/page/b_plus_tree_leaf_page.h \
    src/storage/page/b_plus_tree_leaf_page.cpp \
    src/include/storage/index/b_plus_tree.h \
    src/storage/index/b_plus_tree.cpp \
    src/include/storage/index/index_iterator.h \
    src/storage/index/index_iterator.cpp
  ;;
  1)
    zip $out -urq \
    src/include/buffer/lru_replacer.h \
    src/buffer/lru_replacer.cpp \
    src/include/buffer/buffer_pool_manager.h \
    src/buffer/buffer_pool_manager.cpp
  ;;
  0)
    zip $out -urq src/include/primer/p0_starter.h
  ;;
  *)
    echo "Invalid input: $1"
    print_help
    exit 1
  ;;
esac
echo "Files has been writen into $out.zip..."
unzip -l $out.zip

遇到的问题

• 用vscode调试可以参考
• 中间遇到问题一直想要调试，但是一直跳过断点，原因是要进入debug模式，必须给cmake加参数，估计不加-g就没了在加了cmake参数之后，报错也详细了，之前就只有Segementation Fault
• 从数组中取元素返回的竟然是引用？
  
  
• 
  
• 对于结构的成员默认初始化这样