On Tue, Apr 28, 2015 at 08:00:24PM +0000, Nicholson, Brad (Toronto, ON, CA) 
wrote:
> Hi,
> 
> I noticed an inaccuracy in the transaction isolation docs.  Under the 
> Repeatable Read Isolation Level section it states:
> 
> “The Repeatable Read isolation level only sees data committed before the 
> transaction began; it never sees either uncommitted data or changes committed 
> during transaction execution by concurrent transactions.”
> 
> That is not entirely accurate.  The snapshot starts with the first SQL 
> statement in the transaction, not at the start of the transaction.  Any 
> change that is committed in another transaction after the start of the 
> transaction but before the first SQL statement will be seen.

Yes, we have fixed that for PG 9.5:

        http://www.postgresql.org/docs/devel/static/transaction-iso.html

        This level is different from Read Committed in that a query in a
-->     repeatable read transaction sees a snapshot as of the start of the first
-->     non-transaction-control statement in the transaction, not as of the
        start of the current statement within the transaction. Thus, successive
        SELECT commands within a single transaction see the same data, i.e.,
        they do not see changes made by other transactions that committed after
        their own transaction started.

-- 
  Bruce Momjian  <br...@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +


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