Re: Internal error XX000 with enable_partition_pruning=on, pg 11 beta1 on Debian

On 16 July 2018 at 16:56, Phil Florent <philflorent(at)hotmail(dot)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/
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