Re: SET CONSTRAINTS ALL IMMEDIATE affects SET TRANSACTION READ ONLY

Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
> On 9/9/16 12:39 PM, Tom Lane wrote:
>> I wouldn't really imagine that it's sensible to set READ ONLY
>> mid-transaction at all, but if it means anything to do that, surely
>> it ought to mean that no updates can happen *after* you set it.

> I think there is a bit of code missing in check_transaction_read_only().
> We prevent changing from read-only to read-write after the first query
> but not vice versa. That seems like an oversight.

The comments around the code make it absolutely clear that it's
intentional, not an "oversight". Whether it's a good idea is open
for discussion, certainly, but I don't see how you can imagine that
it wasn't considered.

regards, tom lane