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List:       postgresql-general
Subject:    Re: Sv: Re: Does PostgreSQL check database integrity at startup?
From:       Stephen Frost <sfrost () snowman ! net>
Date:       2017-12-30 23:49:31
Message-ID: 20171230234931.GM2416 () tamriel ! snowman ! net
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* Andreas Joseph Krogh (andreas@visena.com) wrote:
>  SELECT
>     quote_ident(nsp.nspname) || '.' || quote_ident(c.relname),
>     s.setting || '/base/' || db.oid || '/' || c.relfilenode,
>     (pg_stat_file(s.setting || '/base/' || db.oid || '/' || 
> c.relfilenode)).size as size
>  FROM
>     pg_settings s
>     JOIN pg_database db on (s.name = 'data_directory')
>     JOIN pg_class c on (datname = current_database())
>     JOIN pg_namespace nsp on (c.relnamespace = nsp.oid)
>  WHERE
>     relfilenode <> 0
>     AND nsp.nspname !~ '^pg_'
>     AND nsp.nspname <> 'information_schema';
> 
>  Technically speaking, while these queries are correct for PG10, in prior
>  versions of PostgreSQL it's possible to have user schemas that begin
>  with 'pg_' and therefore the filtering in the WHERE clause would have to
>  be more specific.
> 
>  Note that both of these need to be run as a superuser in older versions
>  of PG.   In PostgreSQL 10, a user could be GRANT'd 'pg_read_all_settings'
>  and be able to run the first query.   We don't currently support being
>  able to GRANT a non-superuser the ability to run pg_stat_file(), but
>  that will likely be coming in PG 11.
> 
>  Thanks!
>   
> That doesn't seem to work with custom types:

Nothing in this query referred to types, so I'm not sure what custom
types would have to do with it..?

> andreak@[local]:5433 10.1 andreak=# SELECT                                                 
>    quote_ident(nsp.nspname) || '.' || quote_ident(c.relname),
>    s.setting || '/base/' || db.oid || '/' || c.relfilenode,
>    (pg_stat_file(s.setting || '/base/' || db.oid || '/' || c.relfilenode)).size 
> as size
>  FROM   
>    pg_settings s   
>    JOIN pg_database db on (s.name = 'data_directory')   
>    JOIN pg_class c on (datname = current_database())   
>    JOIN pg_namespace nsp on (c.relnamespace = nsp.oid)   
>  WHERE
>    relfilenode <> 0   
>    AND nsp.nspname !~ '^pg_'
>    AND nsp.nspname <> 'information_schema';
>  ERROR:   could not stat file 
> "/home/andreak/programs/postgresql-10/data/base/22039391/22039392": No such 
> file or directory
>    
> │ public.biginttuple2 │ 
> /home/andreak/programs/postgresql-10/data/base/22039391/22039392 │

Considering this is saaying 'no such file or directory', I'm guessing
that somehow your data directory isn't what is listed in pg_settings..?

Alternatively, perhaps that table was concurrently dropped?

Are you able to provide any specifics about your system?  Does the
database directory exist?  Does that path look reasonable?  I find it
kind of interesting that the OID of the database and the relfilenode are
so close together- exactly what did you do to test this query?

Thanks!

Stephen

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