DB25 SQL Parser

A high-performance, SIMD-optimized SQL parser with comprehensive AST generation

Features • Quick Start • Documentation • Performance • Contributing

Features

• 🚀 Blazing Fast: SIMD-optimized tokenizer with 4.5x speedup
• 🎯 Comprehensive: Supports modern SQL including CTEs, window functions, and more
• 🛡️ Secure: SQLite-inspired depth protection against stack overflow
• 🔧 Extensible: Clean architecture for easy feature additions
• 📊 Visual AST: Professional AST viewer with colored tree output
• 💾 Zero-Copy: Efficient memory usage with string_view throughout
• 🏗️ Modern C++23: Leverages latest language features

Quick Start

Prerequisites

• C++23 compatible compiler:
  • Apple Clang 16.0+ (for deducing this support)
  • GCC 13+
  • Clang 16+
  • MSVC 2022+ (v19.32+)
• CMake 3.20 or higher
• SIMD support (SSE4.2 minimum, AVX2 recommended)

Build and Install

# Clone the repository
git clone https://github.com/space-rf-org/db25-sql-parser.git
cd db25-sql-parser

# Build (clean build from scratch)
mkdir -p build && cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make -j$(nproc)

# Run tests
make test

# Generate visual AST dumps
make generate_ast_dumps

# Install (optional)
sudo make install

Basic Usage

#include <db25/parser/parser.hpp>
#include <iostream>

int main() {
    db25::parser::Parser parser;
    
    auto result = parser.parse("SELECT * FROM users WHERE age > 18");
    
    if (result) {
        std::cout << "Parse successful!" << std::endl;
        // Work with AST...
    } else {
        std::cerr << "Parse error: " << result.error().message << std::endl;
    }
    
    return 0;
}

AST Viewer

Visualize your SQL queries as beautiful syntax trees:

# From command line
echo "SELECT * FROM users" | ./ast_viewer

# From file
./ast_viewer --file tests/showcase_queries.sqls --index 1

# With statistics
./ast_viewer --stats --file queries.sqls --all

Example AST Output (click to expand)

╔══════════════════════════════════════════════════════════════╗
║          DB25 SQL Parser - AST Viewer v1.0                  ║
╚══════════════════════════════════════════════════════════════╝

SQL: SELECT name, RANK() OVER (PARTITION BY dept ORDER BY salary DESC) FROM employees

Abstract Syntax Tree:
──────────────────────────────────────────────────────────────
└─ SELECT [#1, 2 children]
   ├─ SELECT LIST [#3, 2 children]
   │  ├─ COLUMN: name [#2]
   │  └─ WINDOW FUNC: RANK [#4, 1 children]
   │     └─ WINDOW [#5, 2 children]
   │        ├─ PARTITION BY [#6, 1 children]
   │        │  └─ COLUMN: dept [#7]
   │        └─ ORDER BY [#9, 1 children]
   │           └─ COLUMN: salary [#8, DESC]
   └─ FROM [#11, 1 children]
      └─ TABLE: employees [#10]
──────────────────────────────────────────────────────────────

Supported SQL Features

✅ Data Query Language (DQL)

• SELECT with all standard clauses
• JOINs (INNER, LEFT, RIGHT, FULL, CROSS, LATERAL)
• Subqueries (scalar, IN, EXISTS, correlated)
• CTEs including recursive
• Window functions with frames
• Set operations (UNION, INTERSECT, EXCEPT)
• GROUPING SETS, CUBE, ROLLUP

✅ Data Manipulation Language (DML)

• INSERT (VALUES, SELECT, DEFAULT VALUES)
• UPDATE with complex expressions
• DELETE with USING clause
• RETURNING clause

✅ Data Definition Language (DDL)

• CREATE TABLE/INDEX/VIEW
• ALTER TABLE
• DROP with CASCADE

✅ Advanced Features

• CASE expressions
• CAST operations
• Complex expressions with precedence
• String, date, and math functions
• Aggregate functions

Performance

Component	Performance	Notes
Tokenizer	4.5x faster	SIMD-optimized
Parser	~100K queries/sec	O(1) dispatch
Memory	Zero fragmentation	Arena allocator
Depth	1001 levels	Stack protection

Documentation

• 📖 User Manual - Complete usage guide
• 🔧 Developer Guide - Architecture and extension guide
• 📝 API Reference - Detailed API documentation
• 🎯 Examples - Comprehensive SQL examples

Project Structure

db25-sql-parser/
├── include/db25/         # Public headers
│   ├── ast/             # AST node definitions
│   ├── parser/          # Parser interface
│   └── memory/          # Memory management
├── src/                 # Implementation
│   ├── parser/          # Parser implementation
│   ├── ast/             # AST utilities
│   └── memory/          # Arena allocator
├── external/            # Submodules
│   └── tokenizer/       # SIMD tokenizer (protected)
├── tests/               # Test suites & test data
│   ├── showcase_queries.sqls  # Example queries
│   ├── test_*.cpp       # Unit tests
│   └── test_all_queries.sh    # Batch testing script
├── tools/               # Tool source code
│   └── ast_viewer.cpp   # AST visualization tool
├── bin/                 # Compiled executables
│   └── ast_viewer       # Ready-to-use tools
├── scripts/             # Utility scripts
│   └── test_all_queries.sh  # Batch testing (copy)
├── docs/                # Documentation
└── build/               # Build output (git-ignored)

Building and Testing

Clean Build from Scratch

# Remove any existing build artifacts
rm -rf build

# Create fresh build directory
mkdir build && cd build

# Configure with all features
cmake -DCMAKE_BUILD_TYPE=Release \
      -DBUILD_TESTS=ON \
      -DBUILD_TOOLS=ON \
      ..

# Build everything
make -j$(nproc)

# Run all tests
make test

# Or run tests individually
./test_parser_basic
./test_join_comprehensive
./test_window_functions
./test_cte

# Generate AST dumps for visualization
make generate_ast_dumps

# View generated dumps
ls /tmp/db25_ast_dumps/

Debug Build

cmake -DCMAKE_BUILD_TYPE=Debug -DBUILD_TESTS=ON ..
make -j$(nproc)

Contributing

We welcome contributions! Please see our Developer Guide for details on:

• Architecture overview
• Adding new features
• Testing guidelines
• Code style
• Performance optimization

Quick Contribution Guide

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Write tests first (TDD approach)
4. Implement your feature
5. Ensure all tests pass (make test)
6. Update documentation
7. Submit a Pull Request

Performance Benchmarks

Benchmark Results (click to expand)

System: Apple M1 Pro, 32GB RAM
Compiler: Apple Clang 17.0.0
Build: Release with -O3 -march=native

Tokenization Performance:
- Scalar:    220,000 tokens/sec
- SSE4.2:    550,000 tokens/sec
- AVX2:      880,000 tokens/sec
- AVX512:    990,000 tokens/sec

Parse Performance:
- Simple SELECT:     1.2 μs
- Complex JOIN:      8.5 μs
- Recursive CTE:     15.3 μs
- Window Functions:  12.7 μs

Memory Usage:
- Node Size:         64 bytes
- Arena Block:       4 MB
- Fragmentation:     0%

Architecture Highlights

• Zero-Copy Design: String views throughout for minimal allocations
• SIMD Tokenizer: Runtime CPU detection for optimal performance
• Arena Allocation: Fast, cache-friendly memory management
• Depth Protection: Safe recursive descent with stack guards
• Modern C++23: Concepts, ranges, and advanced template features

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Tokenizer SIMD optimizations inspired by simdjson
• Parser architecture influenced by PostgreSQL and DuckDB
• Arena allocator based on game engine techniques
• Depth guard pattern from SQLite

Support

• 🐛 Report Issues
• 💡 Request Features
• 📧 Contact: chiradip@chiradip.com

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Built with ❤️ using modern C++23

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