Marc Mamin <m.ma...@intershop.de> writes:
> > Yes, I undersand that serial is just a hint at table creation time, but is
> > there a place in catalog where we can see if the table was created using
> > 'serial' ?
>
> No. Where the docs say "these are equivalent", they mean that very literally.
>
> > The difference we see between the source and target database is that a
> > schema prefix is displayed with the sequence on one side, and not on the
> > other..
>
> This likely has to do with the search_path settings being different in the
> sessions inspecting the two DBs. I do not think it is related to serial-ness
> at all, it's just the normal behavior of regclass_out for the OID constant
> that's the argument of nextval().
>
> regards, tom lane
Hello,
it seems that our problem had nothing to do with serial, but with the way
schema prefixes are handled in column default values.
pg_attrdef.adsrc:
filled when the defaut value is defined. contains a schema prefix only when
required at this creation time. Is constant afterwards.
pg_get_expr(adbin, adrelid)
the returned expession is dynamic: the schema prefix is returned only when
the sequence schema is not part of the current search_path.
This behavior is understandable but it make it uncomfortable to compare table
definitions between different sources.
Moreover a pg_dump->restore might in some cases modify the value of
pg_attrdef.adsrc
best regards,
Marc Mamin
as test:
set search_path='admin';
create table foo1 (n1 serial);
set search_path='oms';
create table admin.foo2 (n2 serial);
select a.attname, ad.adsrc, pg_get_expr(adbin, adrelid)
FROM pg_attribute a
JOIN pg_attrdef ad ON (a.attnum=ad.adnum and a.attrelid=ad.adrelid)
WHERE a.attrelid IN (Select oid from pg_class where relname
in('foo1','foo2'));
n1 nextval('foo1_n1_seq'::regclass)
nextval('admin.foo1_n1_seq'::regclass)
n2 nextval('admin.foo2_n2_seq'::regclass)
nextval('admin.foo2_n2_seq'::regclass)
set search_path='admin';
select a.attname, ad.adsrc, pg_get_expr(adbin, adrelid)
FROM pg_attribute a
JOIN pg_attrdef ad ON (a.attnum=ad.adnum and a.attrelid=ad.adrelid)
WHERE a.attrelid IN (Select oid from pg_class where relname
in('foo1','foo2'));
n1 nextval('foo1_n1_seq'::regclass)
nextval('foo1_n1_seq'::regclass)
n2 nextval('admin.foo2_n2_seq'::regclass)
nextval('foo2_n2_seq'::regclass)
