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From "Bernt M. Johnsen" <Bernt.John...@Sun.COM>
Subject Re: [jira] Commented: (DERBY-2060) SET CURRENT ISOLATION in ref.man refers java.sql.Connection.setTransactionLevel instead of java.sql.Connection.setTransactionIsolation
Date Thu, 30 Nov 2006 11:00:05 GMT
>>>>>>>>>>>> Kim Haase wrote (2006-11-29 11:31:52):
> Do you mean SET ISOLATION rather than SET TRANSACTION? (I don't have 
> access to the SQL 2003 standard.)

According to the SQL standard, the syntax should be SET TRANSACTION

In Derby this is implemented as SET CURRENT ISOLATION.....

> It seems that we have two issues here.
> 1) The desired change in SET ISOLATION behavior should be in a separate 
> bug -- maybe DERBY-2064, which is not a documentation bug and where it 
> is not clear right now what the needed change is, or maybe a new bug 
> with the broader change.

Yes. Actually we have 3 alternatives on this
1) Change network client driver behaviour to be like the embedded
   driver ,
2) change embedded driver behaviour to be like the client driver, or
3) change Derby to be compliant with the SQL standard

I prefer 3.

> 2) Should we document the current behavior in the meantime, while 
> waiting for the fixes? 

Yes, I think so.

> If so, what exactly is the current behavior? This 
> is my understanding -- please correct as necessary:
> If there is an active transaction, the network client driver always 
> commits the active transaction if either SET ISOLATION or 
> Connection.setTransactionIsolation is called. It does this even if the 
> statement or method call does not actually change the isolation level 
> (that is, if it sets the isolation level to its current value). The 
> embedded driver also always commits the active transaction if SET 
> ISOLATION is called. However, if Connection.setTransactionIsolation is 
> called, the embedded driver commits the active transaction only if the 
> call to Connection.setTransactionIsolation actually changes the 
> isolation level.

That is my understanding of the current sematics.

Bernt Marius Johnsen, Database Technology Group, 
Staff Engineer, Technical Lead Derby/Java DB
Sun Microsystems, Trondheim, Norway

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