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WAL termacronym

write-ahead log — durability mechanism for DBs

Changes are written to a sequential log before being applied to data files. Crash recovery replays the log. Foundation of durability for Postgres, MySQL, most LSM trees, and Kafka.

aliases: write-ahead log, redo log

topics: databases, internals, postgres

references:

• Postgres — WAL
• DDIA Ch. 3 — Storage and Retrieval