| From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
|---|---|
| To: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Greg Stark <stark(at)mit(dot)edu>, Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Greg Sabino Mullane <greg(at)turnstep(dot)com>, Marti Raudsepp <marti(at)juffo(dot)org>, Noah Misch <noah(at)leadboat(dot)com>, Tomas Vondra <tv(at)fuzzy(dot)cz>, Atri Sharma <atri(dot)jiit(at)gmail(dot)com>, Svenne Krap <svenne(at)krap(dot)dk> |
| Subject: | Re: Final Patch for GROUPING SETS |
| Date: | 2015-05-12 03:43:36 |
| Message-ID: | 61362087-28F3-49E5-873C-0DBCE58FD0B5@2ndquadrant.com |
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| Lists: | pgsql-hackers |
>I think the problem is "just" that for each variable, in each grouping
>set - a very large number in a large cube - we're recursing through the
>whole ChainAggregate tree, as each Var just points to a var one level
>lower.
For small values of very large, that is. Had a little thinko there. Its still fault of recursing down all these levels, doing nontrivial work each time.
--
Please excuse brevity and formatting - I am writing this on my mobile phone.
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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