Re: Overhead cost of Serializable Snapshot Isolation

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Greg Sabino Mullane <greg(at)endpoint(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Overhead cost of Serializable Snapshot Isolation
Date: 2011-10-11 20:32:45
Message-ID: 201110112032.p9BKWj504147@momjian.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Greg Sabino Mullane wrote:
-- Start of PGP signed section.
> > If the normal default_transaction_isolation = read committed and all
> > transactions that require serializable are explicitly marked in the
> > application then there is no way to turn off SSI without altering the
> > application. That is not acceptable, since it causes changes in
> > application behaviour and possibly also performance issues.
>
> Performance, perhaps. What application behavior changes? Less
> serialization conflicts?
>
> > We should provide a mechanism to allow people to upgrade to 9.1+
> > without needing to change the meaning and/or performance of their
> > apps.
>
> That ship has sailed.

Simon seems to value backward-compatibility more than the average
hackers poster. The lack of complaints about 9.1 I think means that the
hackers decision of _not_ providing a swich was the right one.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 2011-10-11 20:33:30 Re: Overhead cost of Serializable Snapshot Isolation
Previous Message Simon Riggs 2011-10-11 20:29:19 Re: Overhead cost of Serializable Snapshot Isolation