On Wed, 2024-10-09 at 18:07 +0800, iseki zero wrote: > I found it difficult to understanding some paragraph in the document > "Concurrency control" section. > > > The Repeatable Read mode provides a rigorous guarantee that each > transaction sees a completely stable view of the database. However, this > view will not necessarily always be consistent with some serial (one at > a time) execution of concurrent transactions of the same level. For > example, even a read-only transaction at this level may see a control > record updated to show that a batch has been completed but/not/see one > of the detail records which is logically part of the batch because it > read an earlier revision of the control record. Attempts to enforce > business rules by transactions running at this isolation level are not > likely to work correctly without careful use of explicit locks to block > conflicting transactions. > > At: > https://www.postgresql.org/docs/17/transaction-iso.html#XACT-REPEATABLE-READ:~:text=The%20Repeatable%20Read%20mode,to%20block%20conflicting%20transactions. > > Specifically, I can't understand the example. I think this is referring to this example: https://wiki.postgresql.org/wiki/SSI#Deposit_Report Yours, Laurenz Albe
