wal-and-xlog
Data & DatabaseAdd or modify a PostgreSQL WAL / XLOG record — covers choosing built-in rmgr vs Generic WAL (generic_xlog.c) vs custom rmgr (RegisterCustomRmgr), the XLogInsert + XLogRegisterBuffer idiom, writing a correct redo function, FPI / hint-bit (MarkBufferDirtyHint) rules, full-page-write handling, updating rmgrdesc + pg_waldump output, and bumping XLOG_PAGE_MAGIC when format changes. Use whenever a PG patch emits XLogInsert, adds an access method that needs durability, writes or modifies a redo function, registers a custom rmgr via RegisterCustomRmgr, or reviews a patch that changes WAL-record formats. Skip for MySQL binlog / GTID / row-based logging, SQLite WAL journal mode, Kafka log compaction / segment retention, pgbackrest / barman / wal-g operational config, recovery.conf / standby.signal DBA-side configuration, and generic write-ahead-logging theory or ARIES algorithm questions.