From: Gaetano Mendola <mendola@bigfoot.com>
Subject: Re: A transaction in transaction? Possible?
Date: Thu, 11 Nov 2004 09:10:56 +0100
Organization: PYRENET Midi-pyrenees Provider
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Message-ID: <41931E90.2050108@bigfoot.com>
References: <20041110095352.GA55504@winnie.fuhr.org>
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To: Achilleus Mantzios <achill@matrix.gatewaynet.com>
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In-Reply-To: <Pine.LNX.4.44.0411101256590.6883-100000@matrix.gatewaynet.com>
To: pgsql-sql@postgresql.org

Achilleus Mantzios wrote:
> O Michael Fuhr έγραψε στις Nov 10, 2004 :
> 
> 
>>On Wed, Nov 10, 2004 at 12:45:19AM -0800, Riccardo G. Facchini wrote:
>>
>>
>>>Sorry, but I understand that your example is not really about nested
>>>transactions, but about sequential transactions.
>>
>>Here's a more elaborate example.  If this doesn't demonstrate the
>>capability you're looking for, then please provide an example of
>>what you'd like to do and describe the desired behavior.
>>
>>CREATE TABLE person (id SERIAL PRIMARY KEY, name TEXT NOT NULL);
>>
>>BEGIN;
>>    INSERT INTO person (name) VALUES ('Alice');
>>
>>    SAVEPOINT s1;
>>        INSERT INTO person (name) VALUES ('Bob');
>>
>>	SAVEPOINT s2;
>>	    INSERT INTO person (name) VALUES ('Charles');
>>
>>	    SAVEPOINT s3;
>>	        INSERT INTO person (name) VALUES ('David');
>>	    ROLLBACK TO s3;
>>
>>	    INSERT INTO person (name) VALUES ('Edward');
>>	ROLLBACK TO s2;
>>
>>        INSERT INTO person (name) VALUES ('Frank');
>>    RELEASE s1;
>>
>>    INSERT INTO person (name) VALUES ('George');
>>COMMIT;
> 
> 
> Just a very naive thought....
> Wouldn't make more sense to allow nested begin/commit/rollback blocks?

Is not naive because in this way you can do what you could do with
nested begin/commit/rollback blocks, in this way you can do more.
Think for example in the example above to convert the "ROLLBACK TO s3"
in a "ROLLBACK TO s1", that is impossible to do with begin/commit/rollback blocks.


Regards
Gaetano Mendola