Database Subsystem — Technical Summary

Overview

The database subsystem provides the persistence layer for stellar-core, wrapping the SOCI C++ database-access library to manage connections to SQLite or PostgreSQL backends. It handles schema versioning/migration, connection pooling for worker threads, metrics collection, and a dual-database architecture (main + misc) for SQLite to avoid write-lock contention.

Key Files

• Database.h / Database.cpp — Core Database class; connection management, schema migration, pooling, metrics.
• DatabaseTypeSpecificOperation.h — Visitor pattern for backend-specific (SQLite vs PostgreSQL) code paths.
• DatabaseConnectionString.h / .cpp — Utility to redact passwords from connection strings for logging.
• DatabaseUtils.h / .cpp — Helper for batch-deleting old ledger entries from tables.

Key Classes and Data Structures

Database (inherits NonMovableOrCopyable)