From: | "Albe Laurenz" <laurenz(dot)albe(at)wien(dot)gv(dot)at> |
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To: | "Craig Ringer *EXTERN*" <ringerc(at)ringerc(dot)id(dot)au> |
Cc: | <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: 9.1/9.2 SERIALIZABLE: expected serialization failure between INSERT and SELECT not encountered |
Date: | 2012-10-18 07:10:15 |
Message-ID: | D960CB61B694CF459DCFB4B0128514C2089027E9@exadv11.host.magwien.gv.at |
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Lists: | pgsql-general |
Craig Ringer wrote:
> > Why? They can be serialized. The outcome would be exactly the same
> > if session 2 completed before session 1 began.
>
> Hmm. Good point; so long as *either* ordering is valid it's fine, it's
> only when *both* orderings are invalid that a serialization failure
> would occur. For some reason I had myself thinking that if a conflict
> could occur in either ordering the tx would fail, which wouldn't
really
> be desirable and isn't how it works.
>
> BTW, the issue with the underlying question is that their "name"
column
> is unique. They expected to get a serialization failure on duplicate
> insert into "name", not a unique constraint violation. The question
> wasn't "why doesn't this fail" but "Why does this fail with a
different
> error than I expected". Not that the question made that particularly
clear.
But the unasked question is also answered, right?
Yours,
Laurenz Albe
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