Re: pgsql: doc: add namespace column to pg_buffercache example query

On Thu, Apr  2, 2020 at 07:35:50AM +0200, Peter Eisentraut wrote:
> On 2020-03-31 23:16, Bruce Momjian wrote:
> > doc:  add namespace column to pg_buffercache example query
> > 
> > Without the namespace, the table name could be ambiguous.
> > 
> > Reported-by: adunham@arbormetrix.com
> > 
> > Discussion: https://postgr.es/m/158155175140.23798.2189464781144503491@wrigleys.postgresql.org
> > 
> > Backpatch-through: 9.5
> 
>  <screen>
> -regression=# SELECT c.relname, count(*) AS buffers
> +regression=# SELECT n.nspname, c.relname, count(*) AS buffers
>               FROM pg_buffercache b INNER JOIN pg_class c
>               ON b.relfilenode = pg_relation_filenode(c.oid) AND
>                  b.reldatabase IN (0, (SELECT oid FROM pg_database
>                                        WHERE datname = current_database()))
> -             GROUP BY c.relname
> -             ORDER BY 2 DESC
> +             JOIN pg_namespace n ON n.oid = c.relnamespace
> +             GROUP BY n.nspname, c.relname
> +             ORDER BY 3 DESC
>               LIMIT 10;
> 
> Seems kind of confusing to use INNER JOIN once and then JOIN the other time.

Agreed, INNER removed.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
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