illuca / mini-database

Overview

This project involves the implementation of a mini database management system as part of the coursework for a database systems course. The primary objective is to understand how data is organized within a DBMS and gain hands-on experience in implementing simple relational operators. The project specifically focuses on the select and join operations, which are fundamental to querying in any relational database system.

Code structure

1. load input arguments.
2. init_db() reads an input .txt data file and produce all table files in a certain folder.
3. init_db() build the database.
4. init() initialize the buffer pool and file pool.
5. run() loads and inteprets queries from a .txt query file and invoke sel() and join() to process queries. Query results will be written into a log file.
6. release(): Cleans up resources, freeing buffer and file pools.

Features

• Select Operation: Implementation of the select operator which allows filtering records based on specified conditions.
• Join Operation: Implementation of a nested loop join and a choice of either a hash join or a sort-merge join based on available memory buffer slots.
• Buffer Management: Custom implementation of a memory buffer to manage data pages using a clock-sweep algorithm, emulating buffer replacement strategies used in real-world databases like PostgreSQL.

Design

Table File structure:

Each page and tuple(record) is constant and then we can locate a tuple by page id and tuple id. The calculation of page num and tuple num is written clearly in codes.

HOW TO RUN

Project Structure

$project
├── Makefile
├── README.md
├── bufpool.c
├── bufpool.h
├── data/
├── db.c
├── db.h
├── filepool.c
├── filepool.h
├── main.c
├── ro.c
├── ro.h
├── run-vxdb.sh
├── run.sh
├── test/

cd $project
make
./main [page_size] [buffer_slots] [max_opened_files] [buffer_replacement_policy] [database_folder] [input_data] [queries] [output_log]

# For example:
cd $project
make && ./main 64 6 1 CLS ./data ./test/test1/data_1.txt ./test/test1/query_1.txt ./test/test1/log_1.txt

# Run all test
./run.sh

# Run all test and check memory leak by valgrind
./run-vxdb.sh

If you run with data1, then you can find the output in $project/test/test1/log.txt. By using diff log.txt expected_log_1.txt, you can check if the result is correct.