Re: Add column if not exists (CINE)
От | Simon Riggs |
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Тема | Re: Add column if not exists (CINE) |
Дата | |
Msg-id | 1279759381.1739.11169.camel@ebony обсуждение исходный текст |
Ответ на | Re: Add column if not exists (CINE) (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Add column if not exists (CINE)
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Список | pgsql-hackers |
On Wed, 2010-04-28 at 21:15 -0400, Tom Lane wrote: > I still say > that COR rather than CINE semantics would be appropriate for columns. Viewed from a locking perspective, I would disagree. COR semantics force a table rewrite, in certain cases. That makes it hard to predict externally how long the command will run for. As a DBA, I would want a command that executes without rewrite (if appropriate) or does nothing. Predictable behaviour is the most important concern. That isn't necessarily an argument in favour of CINE, which seems slightly less clear about what we might expect from that, in my reading at least. -- Simon Riggs www.2ndQuadrant.comPostgreSQL Development, 24x7 Support, Training and Services
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