CMU15-445_Database_Management_System

Project 0

Keypoint used in C++:
Template – template < typename T >
Exception

How to create m*n arrays [the 2nd way-inherit]

Google C++ Style Guide
Naming_Class Data Members need a trailing underscore.

** no viable conversion from   
std::unique_ptr<bustub::RowMatrix<int> : temp   
const RowMatrix<T> * : temp.get()  

Consider replacing 'unsigned long' with 'uint64' uint64_t  
C-style casts are discouraged; use static_cast/const_cast/reinterpret_cast  
Convert one int ->int64_t  
const uint64_t size = (static_cast<uint64_t>(rows_) * cols_)  

Project 1

Reference: Database-System-Concepts-7th-Edition Ch13.5 Database Buffer

LRU Replacer
Need to search in o(1), delete; Perform like a stack
Data Structure: Hash map + Linked list

Buffer Pool Manager (BPM) Instance
Data Structure:
std::unordered_map< page_id_t, frame_id_t > page_table_;
std::list< frame_id_t > free_list_;

Class Pages (including content;page_id_ ;pin_count_ = 0; is_dirty_)
Class BPM is friend class of Pages
Class DiskManager(Responsible for writing page from BPM to Disk)

-> Parallel BPM, which has its own latch / Inheritance

Print out the test file to get the whole Gradescope test file!
/Gradescope Test output/

FILE *out;
out = fopen("/autograder/bustub/test/buffer/grading_..._test.cpp", "r");  
// out = fopen("../test/buffer/..._test.cpp", "r");  
char ch;  
while ((ch = getc(out)) != EOF) {  
    putchar(ch);  
}  
fclose(out);  

Get the path for testing on Gradescope using getcwd().
#include < direct.h >; (Windows)
#include < unistd.h >; (Linux/Mac)
int MAX_PATH = 10000;
char buffer[MAX_PATH];
std::cout « getcwd(buffer, MAX_PATH);

latch_.lock();
std::lock_guard< std::mutex > lock(latch_); //better as unlock automatically in Deconstructor

Avoid calling another function with latch (interlock)

ConcurrencyTest
std::vector< std::thread > threads;
std::shared_ptr< BufferPoolManagerInstance > bpm( )
threads.push_back(std::thread( &bpm {

Test Failed: False is not true : Test Timed out
Some part of the code is wrong.(infinite loop , etc)

==5570==ERROR: AddressSanitizer: heap-use-after-free on address 0x000107101a90 at pc 0x000102bca6d0 bp 0x00016d8325b0 sp 0x00016d8325a8

// frame_id = &(victimize_list_.front());  
*frame_id = victimize_list_.front();  

Google C++ Style Guide
Clang-tidy: don’t use else after return;

redundant boolean literal supplied to boolean operator x
if (replacer_->Victim(&frame_id) == false) {
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
!replacer_->Victim(&frame_id)
error: use range-based for loop instead

for (auto iter = page_table_.begin(); iter != page_table_.end(); ++iter) {  
^   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
    (auto & iter : page_table_)  

error: missing username/bug in TODO
// TODO:reset its metadata
^~~~~~~~~~~~~~~~~~~~~~~~~~
// TODO(unknown): reset its metadata