Write-Ahead Logging (WAL)

Cluster focuses on discussions about Write-Ahead Logging (WAL) in databases like PostgreSQL and MySQL, its benefits for write performance, durability, sequential writes, checkpoints, and comparisons to append-only or log-structured storage.

➡️ Stable 0.7x Databases
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#6114
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Keywords

LMDB CS DB LSM ORC LSN PRAGMA API ES WAL log wal write ahead writes transaction append storage database snapshots

Sample Comments

k__ May 31, 2016 View on HN

Isn't this just an issue if there are too much writes?And doesn't a WAL help with that?

GordonS Oct 28, 2022 View on HN

Won't it just... write more WAL files?

lichtenberger Dec 16, 2023 View on HN

Because it has to copy and write entire pages instead of only force a flush of log records due to a WAL?

ffsm8 Dec 20, 2025 View on HN

Isn't that why a WAL exists, so you didn't actually need to do that with eg postgres and other rdbms?

wendroid Apr 9, 2010 View on HN

Nah, PostgreSQL is sticky, it has a Write Ahead Log !!

misframer May 10, 2018 View on HN

This takes advantage of log-structured storage so there isn't any "undoing".

jerrysievert Oct 28, 2022 View on HN

this is exactly what I meant - WAL is your friend.

jdxcode Aug 3, 2020 View on HN

couldn't you just store your data in append-only fashion?

ot Feb 7, 2011 View on HN

You don't have to stop to copy from a log-structured file

barryrandall Jul 16, 2024 View on HN

Write-ahead logs seem to be rediscovered every 3-5 years.