Re: unlogged sequences

On 01.04.22 18:22, Peter Eisentraut wrote:
>
> On 01.04.22 00:43, Tomas Vondra wrote:
>> Hmm, so what about doing a little bit different thing:
>>
>> 1) owned sequences inherit persistence of the table by default
>>
>> 2) allow ALTER SEQUENCE to change persistence for all sequences (no
>> restriction for owned sequences)
>>
>> 3) ALTER TABLE ... SET [UN]LOGGED changes persistence for sequences
>> matching the initial table persistence
>
> Consider that an identity sequence creates an "internal" dependency and
> a serial sequence creates an "auto" dependency.
>
> An "internal" dependency means that the internal object shouldn't really
> be operated on directly.  (In some cases it's allowed for convenience.)
> So I think in that case the sequence must follow the table's persistence
> in all cases.  This is accomplished by setting the initial persistence
> to the table's, making ALTER TABLE propagate persistence changes, and
> prohibiting direct ALTER SEQUENCE SET.

But to make pg_upgrade work for identity sequences of unlogged tables,
we need to allow ALTER SEQUENCE ... SET LOGGED on such sequences. Which
I guess is not a real problem in the end.