Laurenz Albe schrieb am 15.07.2026 um 23:20: >> 4. Most business apps use REPEATABLE READ as an industry standard. > > I am surprised by that statement. > > My experience is that most developers of "business apps" aren't even aware that there > are different transaction isolation levels.
I think, this viewpoint might be based on the fact that it's the default isolation level in MySQL/MariaDB and due to their "marked share", it might be considered a an "industry standard" by a lot of people.
MariaDB Repeatable Read implementation is NOT compliant to the SQL standard only recently has it gotten closer hence the serialization errors the original poster is getting with the later versions of MariaDB
Many people believe they are operating in repeatable read when in reality the database is acting in really odd ways that no one would expect. Why MySQL/MariaDB chose repeatable read isolation as the default when every other database uses Read Committed by default. I do not know MySQL is the odd ball because all the other major databases going back 20+ years use Read Committed.
