On 01/03/18 05:35, Peter Eisentraut wrote:
The SQL standard offers the "chained transactions" feature to address this. The new command variants COMMIT AND CHAIN and ROLLBACK AND CHAIN immediately start a new transaction with the characteristics (isolation level, read/write, deferrable) of the previous one. So code that has particular requirements regard transaction isolation and such can use this to simplify code management.
Oh, is that all it does? That's disappointing, because that's a lot less powerful than how I understand chained transactions. And at the same time relieving, because that's a lot simpler to implement :-).
In Gray & Reuter's classic book, Transaction Processing, they describe chained transactions so that you also keep locks and cursors. Unfortunately I don't have a copy at hand, but that's my recollection, at least. I guess the SQL standard committee had a different idea.
- Heikki
