Re: Tablespace OID, database OID, relfilenode

Thank you Adrian, thank you David!
So, it turns out, it *is* indeed an arbitrary constant...
I have been answered many times RTFM, it is actually the first time I have
being answered RTF source code.
(I searched for 1663 in PG docs, it is there, although not really
"intuitive").

Allow me to humbly propose to maybe at least write somewhere in the DOCs in
a clear way: "This is a number you should know, and it is arbitrary, and in
some functions it will be represented as 'base' ".
It is fundamental to know this when one uses pg_waldump, for example.

Not to start a flame war here, just humbly proposing...

Thanks all again!

On Tue, Jan 17, 2023 at 4:44 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 1/17/23 07:35, Wiwwo Staff wrote:
> > Hi Laurenz,
> > thanks for your answer!
> > Ok, but I don't think "1663" is a sort of constant value for "base",
> > isn't it?
>
> From source:
>
> backend/catalog/postgres.bki
>
> open pg_tablespace
> insert ( 1663 pg_default 10 _null_ _null_ )
> insert ( 1664 pg_global 10 _null_ _null_ )
>
> >
> > Let me clarify my question: how do I get, with a query, from "base" to
> > 1663 (or whatever the value is)?
>
> select * from pg_tablespace ;
> oid | spcname | spcowner | spcacl | spcoptions
> ------+------------+----------+--------+------------
> 1663 | pg_default | 10 | NULL | NULL
> 1664 | pg_global | 10 | NULL | NULL
>
> >
> > On Tue, Jan 17, 2023 at 4:01 PM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at
> > <mailto:laurenz(dot)albe(at)cybertec(dot)at>> wrote:
> >
> > On Tue, 2023-01-17 at 15:48 +0100, Wiwwo Staff wrote:
> > > Quick and to the point:
> > >
> > > If i execute
> > > select pg_relation_filepath('pgbench_accounts');
> > >
> > > I get
> > > pg_relation_filepath
> > > ----------------------
> > > base/5/16398
> > >
> > > where "base" is tablespace, but not tablespace OID, nor
> > tablespace name.
> > > How do I link it to get from "base" the tablespace OID?
> > >
> > > Or, in other words, given table pgbench_accounts, how do I get
> > tablespace OID,
> > > database OID and relfilenode so that I can use this info to
> > filter output of pg_waldump?
> >
> > The tablespace OID is 1663, since "base" is the default tablespace
> > "pg_default".
> >
> > Yours,
> > Laurenz Albe
> > --
> > Cybertec | https://www.cybertec-postgresql.com
> > <https://www.cybertec-postgresql.com>
> >
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>
>