Re: unlogged sequences

On 01.04.22 18:31, Peter Eisentraut wrote:
>> 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.

Here is an updated patch that fixes this pg_dump/pg_upgrade issue and 
also adds a few more comments and documentation sentences about what 
happens and what is allowed.  I didn't change any behaviors; it seems we 
didn't have consensus to do that.

These details about how tables and sequences are linked or not are 
pretty easy to adjust, if people still have some qualms.