Re: Overhead cost of Serializable Snapshot Isolation

On Mon, Oct 10, 2011 at 11:31 PM, Kevin Grittner
<Kevin.Grittner@wicourts.gov> wrote:
> Simon Riggs <simon@2ndQuadrant.com> wrote:
>
>> How do we turn it on/off to allow the overhead to be measured?
>
> User REPEATABLE READ transactions or SERIALIZABLE transactions.  The
> easiest way, if you're doing it for all transactions (which I
> recommend) is to set default_transaction_isolation.

Most apps use mixed mode serializable/repeatable read and therefore
can't be changed by simple parameter. Rewriting the application isn't
a sensible solution.

I think it's clear that SSI should have had and still needs an "off
switch" for cases that cause performance problems.

-- 
 Simon Riggs                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services