On 16 July 2018 at 16:56, Phil Florent <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
