Esc
↑↓ navigate   Enter open   Esc close

Databases & SQL

Write-Ahead Log

/raɪt əˈhed lɒɡ/

Definition

A journal (WAL) recording all changes before applying them to data files — enables crash recovery and replication.

Example in context

"PostgreSQL's WAL means if the server crashes mid-write, it replays the log on restart and recovers consistently."

Related terms

  • Replication — Copying data from a primary database to one or more replicas to improve read performance and provide failover capability.
  • ACID — Four properties guaranteeing reliable database transactions: Atomicity, Consistency, Isolation, and Durability.

Practice this term

Master Write-Ahead Log in context by working through exercises in the Databases & SQL module. You'll see the term used in real engineering scenarios with multiple-choice, fill-in-the-blank, and matching drills.

Practice in exercises → Browse all words

Frequently Asked Questions

What does "Write-Ahead Log" mean?

A journal (WAL) recording all changes before applying them to data files — enables crash recovery and replication.

How do you pronounce "Write-Ahead Log"?

"Write-Ahead Log" is pronounced /raɪt əˈhed lɒɡ/.

Can you use "Write-Ahead Log" in a sentence?

"PostgreSQL's WAL means if the server crashes mid-write, it replays the log on restart and recovers consistently."