Re: Feedback on table expansion hook (including patch)

On 07.05.20 10:11, Erik Nordström wrote:
> I am looking for feedback on the possibility of adding a table expansion 
> hook to PostgreSQL (see attached patch). The motivation for this is to 
> allow extensions to optimize table expansion. In particular, TimescaleDB 
> does its own table expansion in order to apply a number of 
> optimizations, including partition pruning (note that TimescaleDB uses 
> inheritance since PostgreSQL 9.6 rather than declarative partitioning ). 
> There's currently no official hook for table expansion, but TimescaleDB 
> has been using the get_relation_info hook for this purpose. 
> Unfortunately, PostgreSQL 12 broke this for us since it moved expansion 
> to a later stage where we can no longer control it without some pretty 
> bad hacks.

Unlike the get_relation_info_hook, your proposed hook would *replace* 
expand_inherited_rtentry() rather than just tack on additional actions. 
That seems awfully fragile.  Could you do with a hook that does 
additional things rather than replace a whole chunk of built-in code?