Re: Isolation levels

#1

Razvan Socol wrote:

Quote:

Please read the following posts by Craig Freedman, member of the SQL
Server query execution team:
http://blogs.msdn.com/craigfr/archiv...ion-level.aspx
http://blogs.msdn.com/craigfr/archiv...ion-level.aspx
http://blogs.msdn.com/craigfr/archiv...ion-level.aspx

Is the behaviour described in these posts the *correct* behaviour, as
defined by ANSI SQL standards, considering the Read Committed and
Repetable Read isolation levels, respectively ? Do other DBMS-s behave
the same way ? I am aware that the behaviour would be different if we
use snapshot isolation, but I'm interested how things *should* work
without snapshot isolation.

I'd like some responses from people who know really well the ANSI SQL
standard and the isolation levels defined in it.

Thinking you might get a better response from comp.databases, I am
cross-posting your question there.

#2

Bob Badour wrote:

Quote:

Razvan Socol wrote:
Please read the following posts by Craig Freedman, member of the SQL
Server query execution team:
http://blogs.msdn.com/craigfr/archiv...ion-level.aspx
http://blogs.msdn.com/craigfr/archiv...ion-level.aspx
http://blogs.msdn.com/craigfr/archiv...ion-level.aspx

Is the behaviour described in these posts the *correct* behaviour, as
defined by ANSI SQL standards, considering the Read Committed and
Repetable Read isolation levels, respectively ? Do other DBMS-s behave
the same way ? I am aware that the behaviour would be different if we
use snapshot isolation, but I'm interested how things *should* work
without snapshot isolation.

I'd like some responses from people who know really well the ANSI SQL
standard and the isolation levels defined in it.

Assuming he is correct about the behavior, SQL Server is compliant
with ANSI SQL in the areas he covered. Of course, the 'snapshot'
addition is not part of Standard SQL. For more information on
transaction isolation, see our tutorial on SQL92, directly at "http://
www.firstsql.com/tutor5.htm#isolation".

His information on SQL Server is incomplete, and I can't tell your
about the compliance of other SQL DBMSs except, that is, our product
-- FirstSQL/J. FirstSQL/J is fully compliant with the 4 Transaction
Isolation Levels of SQL92.

Quote:

Thinking you might get a better response from comp.databases, I am
cross-posting your question there.

Thanks, Bob!

--
Lee Fesperman, FFE Software, Inc. (http://www.firstsql.com)
================================================== ============
* The Ultimate DBMS is here!
* FirstSQL/J Object/Relational DBMS (http://www.firstsql.com)

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Re: Isolation levels

comp.databases comp.databases

Re: Isolation levels - 05-15-2007 , 02:41 PM

Re: Isolation levels - 05-17-2007 , 02:10 PM