Architecture

GhostSQL is built with a modular architecture to ensure scalability and ease of development.

Core Components

1. Protocol Layer (internal/protocol)

Handles the PostgreSQL wire protocol. It is responsible for parsing incoming packets, managing connections, and formatting response messages (like RowDescription and DataRow).

2. Parser (internal/parser)

A custom SQL parser that converts SQL strings into an Abstract Syntax Tree (AST). It includes: * Lexer: Tokenizes the input string. * Parser: Validates syntax and builds the AST.

3. Executor (internal/executor)

The engine that executes the AST. It handles table scans, join logic, filtering (WHERE), sorting (ORDER BY), and vector similarity computations.

4. Storage Engine (internal/storage)

Manages on-disk data persistence. * DatabaseInstance: Represents a single database. * Table: Manages rows, schema, and indexes. * Slotted Page Storage: Efficiently manages binary data on disk.

Flow of a Query

1. Client Connection: Client connects via psql.
2. Protocol Handshake: Protocol layer handles authentication and startup.
3. Request: Client sends a query string.
4. Parse: Parser converts string to AST.
5. Execute: Executor processes the AST using the Storage Engine.
6. Response: Protocol layer sends results back to the client.