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(at)arbormetrix(dot)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(at)momjian(dot)us> https://momjian.us
EnterpriseDB https://enterprisedb.com

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