Re: WIP patch for parameterized inner paths

From: Robert Haas Tom Lane pgsql-hackers(at)postgresql(dot)org Re: WIP patch for parameterized inner paths 2012-01-26 19:48:54 CA+TgmoZoRxfWQYU8YxG80zwMwDVc9JkRCL7O4ph0KEJjyFWh1A@mail.gmail.com (view raw, whole thread or download thread mbox) 2012-01-17 05:06:54 from Tom Lane  2012-01-17 13:45:37 from Dimitri Fontaine  2012-01-17 16:02:34 from Greg Smith  2012-01-18 08:04:14 from Mark Kirkwood  2012-01-25 16:24:13 from Tom Lane   2012-01-25 17:29:30 from Robert Haas    2012-01-25 18:24:35 from Tom Lane     2012-01-25 19:47:49 from "David E(dot) Wheeler"      2012-01-25 20:19:34 from Tom Lane       2012-01-25 20:24:59 from "David E(dot) Wheeler"     2012-01-25 21:57:08 from Robert Haas      2012-01-26 23:03:41 from Tom Lane     2012-01-26 09:14:53 from Cédric Villemain   2012-01-26 14:14:42 from Robert Haas    2012-01-26 16:04:52 from Tom Lane     2012-01-26 16:54:37 from Robert Haas      2012-01-26 17:01:04 from Robert Haas      2012-01-26 19:27:40 from Tom Lane       2012-01-26 19:48:54 from Robert Haas        2012-01-26 20:06:38 from Tom Lane pgsql-hackers
```On Thu, Jan 26, 2012 at 2:27 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>>> Is there a guard in here against joining a parameterized path to an
>>>> intermediate relation when no SJ is involved?  In other words, if
>>>> we're joining a parameterized path on A to a path on B, then either
>>>> the join to B should satisfy at least part of the parameterization
>>>> needed by A, or there should be a special join with A and B on one
>>>> side and a relation that satisfies at least part of the
>>>> parameterization of A on the other.
>
> I've implemented this idea, recast a bit to prevent generating a
> parameterized join path in the first place unless it depends on a
> parameter from a relation for which there's a join ordering constraint
> still outstanding.  It seems to get us to where the planning time
> penalty is only about 10%, which frankly is probably less than sampling
> error considering the small set of test cases I'm looking at.

Awesome.  If you can post the updated patch, I'll poke at it a little
more and see if anything jumps out at me, but that sounds promising.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

```

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