Re: Some problems regarding the self-join elimination code

On 4/10/25 14:39, Andrei Lepikhov wrote:
> On 4/10/25 13:36, Alexander Korotkov wrote:
>> On Wed, Apr 9, 2025 at 10:39 AM Andrei Lepikhov <lepihov@gmail.com> 
>> wrote:
>>> It seems we are coming to the conclusion that join removal optimisation
>>> may do something out of ChangeVarNodes resposibility. Before further
>>> complicating of this function code I would like to know opinion of Tom,
>>> who initially proposed [1] to use this routine. May be better a) return
>>> to more specialised change_relid / sje_walker machinery or b) move
>>> ChangeVarNodes out of rewriteManip and make it multi-purpose routine,
>>> allowing to transform expression that may happen after a Var node 
>>> change?
>>
>> What about adding a callback to ChangeVarNodes_context that would
>> called for each RestrictInfo after changing varnodes itself?  SJE
>> could use a callback that replaces OpExpr with NullTest when needed.
> I think it is doable, of course. Just looking forward a little, it may 
> need more complication in the future (SJE definitely should be widened 
> to partitioned tables) and it may be simpler to have two different 
> routines for two different stages of planning. 
To provide some food for thought, here is a draft in attachment which 
addresses both issues: RestrictInfo relid replacement and move 
SJE-specific code out of the ChangeVarNodes routine (callback approach).

-- 
regards, Andrei Lepikhov