pgstattuple_approx for toasted table

2019-03-03 Thread Mariel Cherkassky
Hi,
I was testing pgstattuple and I realized that pgstattuple is working on
toasted table but pgstattuple_approx is raising the next error msg :

ERROR:  "pg_toast_18292" is not a table or materialized view

ahm, is that because the pgstattuple_approx uses visibility map ? Can
someone explain ? tnx.


Re: pgstattuple_approx for toasted table

2019-03-03 Thread Laurenz Albe
Mariel Cherkassky wrote:
> I was testing pgstattuple and I realized that pgstattuple is working on 
> toasted table but pgstattuple_approx is raising the next error msg : 
> 
> ERROR:  "pg_toast_18292" is not a table or materialized view
> 
> ahm, is that because the pgstattuple_approx uses visibility map ? Can someone 
> explain ? tnx.

You are right; here is the code:

/*
 * We support only ordinary relations and materialised views, because we
 * depend on the visibility map and free space map for our estimates about
 * unscanned pages.
 */
if (!(rel->rd_rel->relkind == RELKIND_RELATION ||
  rel->rd_rel->relkind == RELKIND_MATVIEW))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 errmsg("\"%s\" is not a table or materialized view",
RelationGetRelationName(rel;

Yours,
Laurenz Albe

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