Re: Our trial to TPC-DS but optimizer made unreasonable plan - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Our trial to TPC-DS but optimizer made unreasonable plan
Date
Msg-id 19116.1440016357@sss.pgh.pa.us
Whole thread Raw
In response to Re: Our trial to TPC-DS but optimizer made unreasonable plan  (Josh Berkus <josh@agliodbs.com>)
List pgsql-hackers
Josh Berkus <josh@agliodbs.com> writes:
> On 08/18/2015 04:40 PM, Qingqing Zhou wrote:
>> Attached please find the WIP patch and also the ANALYZE results.
>> Notes: the patch may not directly apply to head as some network issue
>> here so my Linux box can't talk to git server.

> So, one of the things we previously mentioned is that currently many
> users deliberately use CTEs as an optimization barrier in order to force
> the planner.  Given that, we need some kind of option to force the old
> behavior; either SQL syntax or a GUC option.

I think we already agreed what the syntax would be: ye good olde OFFSET 0
in the subquery.

We could have a GUC option too if people are sufficiently worried about
it, but I think that the need for one hasn't really been proven.
        regards, tom lane



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