Re: Article about supposed "murky" future for Oracle

Thomas Kyte wrote:

> So, tell me -- how do you do a report that gives -- oh say --
> financial data (and hence must sort of return an answer that actually
> existed in the database at some point in time) that consists of
> multiple queries -- each of which must be read consistent not only
> individually -- but with respect to eachother.
Wouldn't you have some sort of a cut off time? I mean you would look at all transactions that happened for a given time-period using a timestamp. If the DBMS kept running sums in the operational system then it buys itself a "writers blocking writers" problem in the normal operations and it wouldn't be normalized either.
As a result the data that is being looked at is stable. RR/Serializable (if chosen) ensures no-one is trying to undo a previously committed transaction but it does not harm incoming new transactions. Maybe I'm naive....

Cheers
Serge

-- 
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab