Re: Read Committed isolation

I guess the big question is whether we want to be teaching isolation
level concepts in our manual.  It is a standard database concept.

---------------------------------------------------------------------------

Oliver Crow wrote:
>
> Hi all,
>
> It seems to me that the PostgreSQL user's manual could be clearer on the
> consequences of using the Read Committed isolation level.
>
> It says "The partial transaction isolation provided by Read Committed
> mode is adequate for many applications" ... "However, for applications
> that do complex queries and updates, it may be necessary to guarantee a
> more rigorously consistent view of the database".
>
> It does not say what types of transactions will cause problems in Read
> Committed mode, or what the consequences of those problems might be.
> This is a point on which the manual ought to be explicit ... the potential
> for intermittent creation of database inconsistencies is serious. For
> example, if information from a select is passed via the application to an
> update, the transaction could reintroduce stale information.
>
> This message provides some good explanation with examples:
> http://archives.postgresql.org/pgsql-hackers/2002-04/msg00150.php
>
>
> It also speaks clearly about when a serializable transaction may need to
> be repeated, and the possible trade off between using serializable or
> SELECT FOR UPDATE.  Could an edited version of that message be included in
> the manual?  (I'd be willing to assist with editing)
>
>
> Thanks, Oliver
>
>
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
> http://www.postgresql.org/users-lounge/docs/faq.html
>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073