| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | Greg Sabino Mullane <greg(at)turnstep(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Re: [COMMITTERS] pgsql: Rewrite GEQO's gimme_tree function so that it always finds a |
| Date: | 2009-12-03 03:53:36 |
| Message-ID: | 29192.1259812416@sss.pgh.pa.us |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-committers pgsql-hackers |
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> Well, when I was testing, I believe I observed that an n-way join with
> 1 cross join was slower to plan than an n-way join with no cross
> joins. ISTM that it should actually be faster, because you should
> plan it like an (n-1)-way join and then do the cross join at the end.
It's not entirely clear to me what case you're describing, but I wonder
whether this was a "flat" join problem or restricted by the collapse
limits.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | User Achernow | 2009-12-03 04:25:46 | libpqtypes - libpqtypes: Fixed how missing types are handled during |
| Previous Message | Robert Haas | 2009-12-03 03:49:48 | Re: Re: [COMMITTERS] pgsql: Rewrite GEQO's gimme_tree function so that it always finds a |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Michael Paquier | 2009-12-03 04:12:23 | Re: pgbench: new feature allowing to launch shell commands |
| Previous Message | Robert Haas | 2009-12-03 03:49:48 | Re: Re: [COMMITTERS] pgsql: Rewrite GEQO's gimme_tree function so that it always finds a |