Re: Hot standby and b-tree killed items

On Fri, 2008-12-19 at 13:47 -0600, Kevin Grittner wrote:
> >>> Simon Riggs  wrote: 
>  
> > max_standby_delay is set in recovery.conf, value 0 (forever) -
> 2,000,000
> > secs, settable in milliseconds. So think of it like a deadlock
> detector
> > for recovery apply.
>  
> Aha!  A deadlock is a type of serialization failure.  (In fact, on
> databases with lock-based concurrency control rather than MVCC, it can
> be the ONLY type of serialization failure.)

The SQL Standard specifically names this error as thrown when "it
detects the inability to guarantee the serializability of two or more
concurrent SQL-transactions". Now that really should only apply when
running with SERIALIZABLE transactions, but I grant you the standard
doesn't explicitly say that.

You give me the strange sense that you want this because of some quirk
in your software, rather than an overwhelming desire to see these two
situations described the same.

I guess making it that SQLSTATE would make it simpler to understand why
the error occurs and also how to handle it (i.e. resubmit). So there
probably is a wide argument for making developers jobs a little easier
by doing it. i.e. usability will be improved if we do that.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support