I get it. Thank you for this precision.

Regards

Phil

________________________________
De : David Rowley <david.row...@2ndquadrant.com>
Envoyé : lundi 16 juillet 2018 07:48
À : Phil Florent
Cc : Tom Lane; Robert Haas; Amit Langote; PostgreSQL Hackers
Objet : Re: Internal error XX000 with enable_partition_pruning=on, pg 11 beta1 
on Debian

On 16 July 2018 at 16:56, Phil Florent 
<philflor...@hotmail.com<mailto:philflor...@hotmail.com>> wrote:

I should post that in the general section but I am confused by the sentence "A 
parent partition is always going to have a lower relid than its children"

It's a little confusing since RelOptInfo has a relid field and so does 
RangeTblEntry. They both have completely different meanings.  RelOptInfo's 
relid is a number starting at 1 and continues in a gapless sequence increasing 
by 1 with each RelOptInfo.  These relids are completely internal to the server 
and don't appear in the system catalog tables.  RangeTblEntry's relid is what's 
in pg_class.oid.

I was talking about RelOptInfo's relid.

Using relids starting at 1 is quite convenient for allowing direct array 
lookups in various data structures in the planner. However it's also required 
to uniquely identify a relation as a single table may appear many times in a 
query, so trying to identify them by their oid could be ambiguous.  Also, some 
RTEKinds don't have storage, e.g a VALUES() clause.

--
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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