Re: Our trial to TPC-DS but optimizer made unreasonable plan

Josh Berkus <josh(at)agliodbs(dot)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