Re: Useless sort by - Mailing list pgsql-performance

From Maciek Sakrejda
Subject Re: Useless sort by
Date
Msg-id AANLkTimK90T2Rb1aaoX=wLXEk5YmmmXjGtNojCn+yoMA@mail.gmail.com
Whole thread Raw
In response to Re: Useless sort by  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
List pgsql-performance
> You could check for volatile functions. I think this could be done safely.

I don't think that's enough. A UDA like last() could have an immutable
sfunc, but still be sensitive to the sort order. I think you'd need
something like a special order-sensitive aggregate definition flag.

---
Maciek Sakrejda | System Architect | Truviso

1065 E. Hillsdale Blvd., Suite 215
Foster City, CA 94404
(650) 242-3500 Main
www.truviso.com

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