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Re: BUG #1231: Probelm with transactions in stored code.

From: Gaetano Mendola <mendola(at)bigfoot(dot)com>
To: Robert Treat <xzilla(at)users(dot)sourceforge(dot)net>
Subject: Re: BUG #1231: Probelm with transactions in stored code.
Date: 2004-08-26 13:08:12
Message-ID: 412DE0BC.9050900@bigfoot.com (view raw or flat)
Thread:
Lists: pgsql-bugs
Robert Treat wrote:

> On Thu, 2004-08-26 at 04:23, Gaetano Mendola wrote:
> 
>>Tom Lane wrote:
>>
>> > Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com> writes:
>> >
>> >>I believe it sees the one that was valid in the snapshot as of the
>> >>beginning of the function.
>> >
>> >
>> > Actually, the problem is that it can see *both* that row and the updated
>> > row; it's a crapshoot which one will be returned by the SELECT INTO.
>>
>>Confirmed, if the last select is:
>>
>>select count(*) into a from test where id=1;
>>
>>this return 2. There is a space for a new bug considering that if the
>>table have the unique index on id that select must return 1.
>>
>> > The reason this can happen is that we're not doing SetQuerySnapshot
>> > between commands of a plpgsql function.  There is discussion going way
>> > way back about whether we shouldn't do so (see the archives).  I think
>> > the major reason why we have not done it is fear of introducing
>> > non-backwards-compatible behavior.  Seems like 8.0 is exactly the right
>> > version to consider doing that in.
>>
>>If my 2 cents are valid I agree with you, what I don't totally agree is why
>>consider this bug as a *feature* in previous 8.0 version.
>>
> 
> I don't think this was ever considered a feature (at least I never found
> any evidence of that) but more the concern was that it was "expected
> behavior" and changing that behavior might toss people into a loop who
> were expecting it. 

Yes, I used the wrong expression is not a feature but a gotcha.
I fairly trust that someone is currently using this behaviour considering it
the good expected one.



Regards
Gaetano Mendola




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Subject: Re: Memory leak
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Subject: Re: BUG #1231: Probelm with transactions in stored code.

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