Re: Problem with oids for table names getting out of sync? - Mailing list pgsql-general

From Omar Eljumaily
Subject Re: Problem with oids for table names getting out of sync?
Date
Msg-id 46150DC9.1090606@omnicode.com
Whole thread Raw
In response to Re: Problem with oids for table names getting out of sync?  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-general
Alvaro and Tom, thanks so much.  I was getting worried that I was going
to have to ask my customers to dump and restore periodically, ugh.  I
think I need to learn a bit more about postgresql internals to help me
with my project.  Not thinking about selecting for oids is kind of
embarrassing.

Thanks,

Omar

Alvaro Herrera wrote:
> omar wrote:
>
>>>> SELECT relfilenode, relname FROM pg_class WHERE relname !~ '^(pg_|sql_)'
>>>> AND relkind = 'r'
>>>>
>>>>
>>>            Oid o = PQftable(_res, i);
>>>
>>>
>>> Um ... are you laboring under some delusion about relfilenode being the
>>> same as relation OID?
>>>
>>>
>>>
>> Apparently I am.  libpq docs claim that "You can query the system table
>> pg_class to determine exactly which table is referenced." for PQftable.
>> I query pg_class and the only column that looks remotely like a unique
>> oid is relfilenode.
>>
>
> select oid, relname from pg_class where ...
>
> relfilenode is just the file name given to the table, which is the same
> as the OID when the table is just created, but changes after certain
> operations (CLUSTER, TRUNCATE, REINDEX for indexes, maybe others)
>
>


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