On 2018-Dec-07, Robert Haas wrote: > Full disclosure: EDB has a feature like this and has for years, but it > uses a subtransaction per statement, not a subtransaction per row.
Well, this implementation only uses one subtransaction per statement; Andres says per-row referring to the case of one INSERT per row, so it's still one statement. > It is indeed useful to customers, but it also does cause its share of > problems. It is *very* easy to burn through a *lot* of XIDs this way, > even with a subtransaction per statement. For example, PL code in > function A can call PL code in function B which can call PL code in > function C, and you throw in a loop here and an EXCEPTION block there > and all kinds of fun ensues. Yeah, I agree that this downside is real. I think our only protection against that is to say "don't do that". Like any other tool, it has upsides and downsides; we shouldn't keep it away from users only because they might misuse it. I would be interested to know if the EDB implementation does something in a better way than this one; then we can improve ours. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
