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A comment on Show HN: Postgres Query Lock Explainer. Parent comment

Re:Show HN: Postgres Query Lock Explainer by LunaSea on Thursday May 18, 2023 @01:15AM (#35984344)
As far as I know, truncate can be rolled back but it is also visible, even before the transaction is commited, to other transactions that started before:

https://www.postgresql.org/docs/current/sql-truncate.html

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Re:Show HN: Postgres Query Lock Explainer by fovc on Friday May 19, 2023 @12:51PM (#36004088)
Ah thank you! Quoting the link for others;

> TRUNCATE is not MVCC-safe. After truncation, the table will appear empty to concurrent transactions, if they are using a snapshot taken before the truncation occurred. See Section 13.6 for more details.

> TRUNCATE is transaction-safe with respect to the data in the tables: the truncation will be safely rolled back if the surrounding transaction does not commit.

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