On Tue, 2025-02-18 at 18:59 +0200, kaido vaikla wrote: > I found a statement: > > Long-running transactions can cause replication lag because the changes made by > these transactions are not replicated until the transaction is committed. > (https://www.percona.com/blog/replication-lag-in-postgresql/) > > > It means: > change made by transaction is not replicated until the transaction is committed? > > And for example > time0: wal on primary > time1: tx1 begin > time2: tx2 begin > time3: tx2 rollback > time4: tx3 begin > time5: tx3 commit > time6: tx1 commit > time7: walsender sends tx1, tx3 to replica, tx2 skipped because rollback > ? I'd say that the article is talking about streaming replication, and the statement is manifestly wrong in the context of streaming replication. All changes, no matter if they are committed or not, will be replicated right away. They just don't become *visible* before the COMMIT is replayed. With logical replication, uncommitted changes are not replicated unless the subscription was created with "streaming" set to something else than "off". Yours, Laurenz Albe -- *E-Mail Disclaimer* Der Inhalt dieser E-Mail ist ausschliesslich fuer den bezeichneten Adressaten bestimmt. Wenn Sie nicht der vorgesehene Adressat dieser E-Mail oder dessen Vertreter sein sollten, so beachten Sie bitte, dass jede Form der Kenntnisnahme, Veroeffentlichung, Vervielfaeltigung oder Weitergabe des Inhalts dieser E-Mail unzulaessig ist. Wir bitten Sie, sich in diesem Fall mit dem Absender der E-Mail in Verbindung zu setzen. *CONFIDENTIALITY NOTICE & DISCLAIMER *This message and any attachment are confidential and may be privileged or otherwise protected from disclosure and solely for the use of the person(s) or entity to whom it is intended. If you have received this message in error and are not the intended recipient, please notify the sender immediately and delete this message and any attachment from your system. If you are not the intended recipient, be advised that any use of this message is prohibited and may be unlawful, and you must not copy this message or attachment or disclose the contents to any other person.
