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From: georgejzhang@gmail.com
Newsgroups: comp.databases.oracle.server
Subject: Question regarding read consistency in Tom Kyte's Expert 10g book
Date: 5 May 2005 09:57:30 -0700
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Hi,

I am reading Chapter one (still beta) of Tom Kyte's new Expert 10g
book (http://oracle.apress.com/), and it is really a good read.

However, I have some questions about the read consistency example (page
20 - 22) - getting the total balance of accounts table (I would have
tested it if I could).  On page 22, table 1-2, what if T7 and T6
interchange their position?  If the transaction updates row4 and
commits before the query reads row4, the query would not know that row4
has been updated, thus getting the total of 1650?  That of course does
not sound right.  Can you explain how that happens?

And another question, the same example on page 20, why do we assume
that the table stores one row per block?  What if all 4 row are stored
in one block?

Thanks

George