From: | Jeroen Ruigrok/asmodai <asmodai(at)wxs(dot)nl> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: constraint modification on todo list |
Date: | 2003-09-12 05:33:37 |
Message-ID: | 20030912053337.GK23805@nexus.ninth-circle.org |
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Lists: | pgsql-hackers |
-On [20030911 15:43], Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
>We can't ALTER a table that's already in use when the first ALTER
>starts, either --- its attempt to exclusive-lock the table will fail.
>But once you get the exclusive lock, you can (in Postgres) perform
>a series of operations without fear that subsequently-started
>transactions will be able to see the incompletely changed state of the
>table. Evidently Oracle can't handle that. That's why they need to
>invent combination operations like MODIFY CONSTRAINT.
As my colleague says:
it is indeed a lazy choice, but super safe and that's the goal.
--
Jeroen Ruigrok van der Werven <asmodai(at)wxs.nl> / asmodai / kita no mono
PGP fingerprint: 2D92 980E 45FE 2C28 9DB7 9D88 97E6 839B 2EAC 625B
http://www.tendra.org/ | http://www.in-nomine.org/~asmodai/diary/
Man inagines that it is death he fears; but what he fears is the unforeseen,
the explosion. What man fears is himself...
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