DEVNOTES.md

High Level Design

This is a high level design of a simple database system. WIP.

Network

Considerations

• Use custom protocol that will be designed later.
• Security is completely out of scope.

SQL

Parser

• Takes a string

• Checks for syntax errors?

• Returns a parse tree

• maybe nom?

Analyzer

• Takes a parse tree
• Checks for semantic errors (for exmaple, no such table)
• Returns a query plan (logical plan)

Optimizer

• Takes a query plan
• Optimizes the query plan
• Returns an optimized query plan (physical plan)

Execution

• Takes a physical plan
• Executes the query
• Returns the result (in what format?)

Storage

• Declares methods:
  • get_by_key(key: bytes) -> bytes
  • put(key: bytes, value: bytes) -> None
  • delete(key: bytes) -> None
  • scan(start_key: bytes, end_key: bytes) -> Iterator[Tuple[bytes, bytes]]

Transactions

• guarantee ACID properties -> WAL

Configuration management

• Config file?

Catalog

• Metadata about tables, columns, indexes, etc.