Re: unable to see new/updated records
Date: Wed, 02 Dec 2009 09:25:39 +0100
Mladen Gogala wrote:
> On Tue, 01 Dec 2009 22:25:09 +0100, GD wrote:
>> That's the law only for serializable transactions, not for "normal" >> transactions.
> Nope. In Oracle RDBMS, transaction can see only the data that was
> committed at the time when the transaction was started. That is always
> the case. Serializable prevents phantom reads by imposing a shared lock
This is not true. Please perform a simple test or consult your Concepts manual:
This is the default transaction isolation level. Each query executed by a transaction sees only data that was committed before the query (not the transaction) began. An Oracle query never reads dirty (uncommitted) data. Because Oracle does not prevent other transactions from modifying the data read by a query, that data can be changed by other transactions between two executions of the query. Thus, a transaction that runs a given query twice can experience both nonrepeatable read and phantoms."
Regards Received on Wed Dec 02 2009 - 02:25:39 CST