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Re: JDBC transaction isolation

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Arne Vajhøj wrote:
> Lew wrote:
>> Richard Maher wrote:
>>> Arne Vajhøj wrote ...
>>>> Almost all database have it at the SQL level:
>>>>
>>>> http://dev.mysql.com/doc/refman/5.5/en/set-transaction.html
>>>> http://www.postgresql.org/docs/9.1/static/sql-set-transaction.html and
>>>> http://www.postgresql.org/docs/9.1/static/transaction-iso.html
>>>> http://msdn.microsoft.com/en-us/library/ms173763.aspx
>>>> http://docs.oracle.com/cd/B10500_01/server.920/a96524/c21cnsis.htm
>>>
>>> Is anyone else of the opinion that Oracle really does not support the
>>> serializable isolation level? (At least not in the way that SQL Server, Rdb,
>>
>> Are you referring to their database product or some other product, such as Java?
>>
>>> and I'm sure others do) That is, it doesn't prevent inserts to the other
>>> txn's result-set,touched-rows by locking but rather fudges some sort of
>>> snapshot/consistent-view of old data. (And even then with restrictions)
>>> Eg: - select count(*) from employees where dept_code=1;
>>
>> They do support SERIALIZABLE isolation, and properly by all evidence:
>>
>> <http://docs.oracle.com/cd/E11882_01/server.112/e26088/statements_10005.htm#SQLRF01705>
>> "ISOLATION LEVEL Clause
>>
>> "Use the ISOLATION LEVEL clause to specify how transactions containing database
>> modifications are handled.
>>
>> "The SERIALIZABLE setting specifies serializable transaction isolation mode as defined in the
>> SQL standard. If a serializable transaction contains data manipulation language (DML) that
>> attempts to update any resource that may have been updated in a transaction uncommitted at
>> the start of the serializable transaction, then the DML statement fails."
>>
>> See also
>> <http://docs.oracle.com/cd/E11882_01/server.112/e25789/consist.htm#BABEAFAH>
>>
>> There's nothing in the definition of SERIALIZABLE transactions that requires locking.
>> <http://en.wikipedia.org/wiki/Isolation_(database_systems)#Serializable>
>>
>> So whatever anyone else's opinion, or yours, the facts seem to be that Oracle Database 
>> properly supports SERIALIZABLE transaction isolation. Why do you ask for opinion when 
>> facts are in evidence?
> 
> They meet the definition for transaction isolation level serializable.

Q.E.D.

> It is more questionable whether MVCC (and Oracle is actually not the
> only database vendor using MVCC != meet what most people associate
> with serializable.

What does that matter? The term "serializable transaction isolation" is a term of art, with a 
specific definition. Whatever "most people" associate with it notwithstanding. It's an objective 
term with testable criteria for compliance. Oracle meets the test.

People are not entitled to wrong opinions on the definitions of terms of art, or any opinions, as to their definition.

> Well - I think should use the database definition and not the
> English definition when it actually is a database.

+1

> But I will not be surprised when somebody ask questions about it.

Surprise at the question is one thing. A correct answer is another.

I'm not evincing surprise at the question, only pointing out that the answer is not a matter of opinion.

-- 
Lew

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JDBC transaction isolation markspace <-@.> - 2012-05-03 07:30 -0700
  Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 11:53 -0400
    Re: JDBC transaction isolation markspace <-@.> - 2012-05-03 11:43 -0700
      Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 15:00 -0400
        Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-03 14:00 -0700
          Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 17:13 -0400
        Re: JDBC transaction isolation "Richard Maher" <maher_rj@hotspamnotmail.com> - 2012-05-04 06:23 +0800
          Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 19:57 -0400
            Re: JDBC transaction isolation Richard Maher <maherrj@googlemail.com> - 2012-05-03 19:08 -0700
              Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 22:34 -0400
                Re: JDBC transaction isolation Richard Maher <maherrj@googlemail.com> - 2012-05-03 20:11 -0700
                Re: JDBC transaction isolation Richard Maher <maherrj@googlemail.com> - 2012-05-03 22:33 -0700
                Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-04 08:27 -0400
                Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-04 06:58 -0700
          Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-03 17:15 -0700
            Re: JDBC transaction isolation Arne Vajhøj <arne@vajhoej.dk> - 2012-05-03 21:22 -0400
              Re: JDBC transaction isolation Lew <lewbloch@gmail.com> - 2012-05-03 18:32 -0700

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