On 26 Mar 2018, at 8:09am, Marco Bambini <ma...@sqlabs.net> wrote: > Is there a better formal description about the "transactions may not overlap" > sentence? > Is there any example about overlapping transactions?
Overlapping transactions occur when a second connection does a BEGIN before the first connection does its COMMIT. It's difficult to present it well without colours or fixed-width fonts, but try this: connection 1: BEGIN CONCURRENT connection 1: -- various database reads and updates connection 2: BEGIN CONCURRENT connection 2: -- various database reads and updates connection 1: COMMIT connection 2: COMMIT (Alternatively the COMMIT lines could occur in the other order. Either way, the transactions are overlapping.) Using normal BEGIN variants, the thread executing the third or fourth lines would be the one which noticed the problem. The thread would be delayed and may eventually return SQLITE_. This new variant BEGIN CONCURRENT ensures that the thread executing the second BEGIN is not delayed, and that instead the error is returned when that connection executes the COMMIT. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
