| From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Cc: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [HACKERS] Aggregate transition state merging vs. hypothetical set functions |
| Date: | 2018-05-21 14:14:58 |
| Message-ID: | d2e1afd4-659c-50d6-1b20-7cfd3675e909@2ndquadrant.com |
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| Lists: | pgsql-hackers |
On 10/13/17 19:01, Tom Lane wrote:
>> Moving on to the exact color of the bikeshed: it seems like the right
>> way to present this to users of CREATE AGGREGATE is in terms of "does
>> the final function modify the transition state?". So maybe the values
>> could be spelled
>> SMODIFY = READ_ONLY ffunc never touches state, ok as window agg
>> SMODIFY = SHARABLE ffunc does some one-time change like sorting,
>> so state merging is OK but not window agg
>> SMODIFY = READ_WRITE ffunc trashes state, can't do merging either
>> I'm not set on these names by any means; anyone have a better idea?
Is "sharable" the preferred spelling, as opposed to "shareable"?
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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