Re: create index on a jsonb timestamp field?

Larry Rosenman <ler(at)lerctr(dot)org> writes:
> On 05/18/2019 8:17 pm, Tom Lane wrote:
>> BTW, I'd had the idea that the GENERATED option in PG v13 would allow
>> setting up this sort of case without bothering with a handwritten
>> trigger, but it seems not:
>>
>> regression=# create table foo(data jsonb, ts timestamptz GENERATED
>> ALWAYS AS ((data->>'ts')::timestamptz) stored);
>> psql: ERROR: generation expression is not immutable
>>
>> I wonder if that's really necessary to insist on?

> Good question. Is that something the project is going to look into?

Well, I was just asking the question, not opining on whether it
was right or wrong. GENERATED is a SQL-spec feature, and it might
be that the semantics the spec calls for wouldn't work without
the restriction. I've not looked...

regards, tom lane