Sean Chittenden wrote:
> > > > Um, why not make it an actual full blown security feature by
> > > > applying the following patch?  This gives PostgreSQL real read
> > > > only transactions that users can't escape from.  Notes about the
> > > > patch:
> > > 
> > > Way nifty.   
> > > 
> > > I vote in favor of this patch (suitably documented & debugged) for 7.5.
> > 
> > Heh, there ain't much to debug: it's pretty straight forward.  I ran
> > all the use cases/syntaxes I could think of and they worked as
> > expected.  It's a pretty chump little ditty that I originally wrote
> > for the sake of the 7.4 PR, but it's proving to be quite useful here
> > in my tree...  though I like the name "jail_read_only_transactions"
> > more...  patch updated for new name.
> 
> Err..  and attached.  -sc

I assume this patch is to control this way of breaking out of a
read-only transaction:

        test=> START TRANSACTION READ ONLY;
        START TRANSACTION
        test=> CREATE TABLE x(y INT);
        ERROR:  transaction IS read-only
        test=> COMMIT;
        COMMIT

        test=> START TRANSACTION READ ONLY;
        START TRANSACTION
        test=> SET transaction_read_only = FALSE;
        SET
        test=> CREATE TABLE x (y INT);
        CREATE TABLE
        test=> COMMIT;
        COMMIT

This seems like a valuable feature, as others have mentioned.  However,
should it also prevent changes to default_transaction_read_only?

What is the use case for this functionality?

Seems someone could easily break out of this by doing:

        test=> START TRANSACTION READ ONLY;
        START TRANSACTION
        test=> COMMIT;
        COMMIT

        test=> START TRANSACTION;
        START TRANSACTION
        test=> CREATE TABLE x (y INT);
        CREATE TABLE

This shows that default_transaction_read_only probably has to be
restricted too by the same variable.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  [EMAIL PROTECTED]               |  (610) 359-1001
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