Re: Passing more context info to selectivity-estimation code - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Passing more context info to selectivity-estimation code
Date
Msg-id 2226.1179680859@sss.pgh.pa.us
Whole thread Raw
In response to Re: Passing more context info to selectivity-estimation code  (Heikki Linnakangas <heikki@enterprisedb.com>)
List pgsql-hackers
Heikki Linnakangas <heikki@enterprisedb.com> writes:
> Tom Lane wrote:
>> Comments, better ideas?

> How about building a separate Var-node for the variable when it's above 
> an outer join?

[ itch... ]  That would be a whole lot *more* invasive than what I'm
proposing now.  It might be an interesting avenue to pursue,
particularly in conjunction with the planner's inability to deal with
non-nullable expressions in subselect outputs below outer joins (which
seems to require some special kind of Var to fix).  But I can't see
back-patching it.
        regards, tom lane


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