Re: Tightening selection of default sort/group operators
От | Peter Eisentraut |
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Тема | Re: Tightening selection of default sort/group operators |
Дата | |
Msg-id | Pine.LNX.4.44.0211300129290.12428-100000@localhost.localdomain обсуждение исходный текст |
Ответ на | Tightening selection of default sort/group operators (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Tightening selection of default sort/group operators
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Список | pgsql-hackers |
Tom Lane writes: > What I'm thinking of doing instead is always looking up the "=" operator > by name, and accepting this as actually being equality if it is marked > mergejoinable or hashjoinable or has eqsel() as its restriction > selectivity estimator (oprrest). If we are looking for a "<" operator > to implement sorting/grouping, then we require "=" to be mergejoinable, > and we use its lsortop operator (regardless of name). My first thought is that this seems to be an awefully backwards way to define operator semantic metadata. I think we either have to flag operators explicitly ("this is the less-than operator"), or we just require that < <= = >= > have certain semantics. I could be happy with both. -- Peter Eisentraut peter_e@gmx.net
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