Re: Overhead cost of Serializable Snapshot Isolation

On Wed, Oct 12, 2011 at 1:44 PM, Florian Pflug <fgp@phlo.org> wrote:
> On Oct11, 2011, at 23:35 , Simon Riggs wrote:
>> On Tue, Oct 11, 2011 at 10:30 PM, Florian Pflug <fgp@phlo.org> wrote:
>>
>>> That experience has taught me that backwards compatibility, while very
>>> important in a lot of cases, has the potential to do just as much harm
>>> if overdone.
>>
>> Agreed. Does my suggestion represent overdoing it? I ask for balance,
>> not an extreme.
>
> It's my belief that an "off" switch for true serializability is overdoing
> it, yes.
>
> With such a switch, every application that relies on true serializability
> for
> correctness would be prone to silent data corruption should the switch ever
> get set to "off" accidentally.
>
> Without such a switch, OTOH, all that will happen are a few more aborts due
> to
> serialization errors in application who request SERIALIZABLE when they
> really
> only need REPEATABLE READ. Which, in the worst case, is a performance issue,
> but never an issue of correctness.

That's a good argument and I accept it.

--
 Simon Riggs                   http://www.2ndQuadrant.com/
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