Re: [HACKERS] Planner drops unreferenced tables --- bug, no?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: wieck(at)debis(dot)com (Jan Wieck)
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Planner drops unreferenced tables --- bug, no?
Date: 1999-09-29 15:04:52
Message-ID: 3863.938617492@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

wieck(at)debis(dot)com (Jan Wieck) writes:
>> It seems to me that the latter query must yield 9 rows (three
>> occurrences of each value) to satisfy the SQL spec. The spec defines
>> the result of a two-query FROM clause to be the Cartesian product of the
>> two tables, period. It doesn't say anything about "only if one or more
>> columns of each table are actually used somewhere".

> Caution here!

> After rewriting there can be many unused rangetable entries
> floating around. Especially if you SELECT from a view, the
> view's relation is still mentioned in the rangetable.

I was thinking of forcing rangetable entries that are marked as
'inFromCl' to be included in the planner's target relation set,
but those not so marked would only get added if referenced, same as now.
Do you think that will not work?

regards, tom lane

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Christof Petig 1999-09-29 15:05:34 Re: [HACKERS] Regression tests on intel for 6.5.2
Previous Message Jan Wieck 1999-09-29 14:52:04 Re: [HACKERS] Planner drops unreferenced tables --- bug, no?