Re: Add a new table for Transaction Isolation?

On Sat, Apr 25, 2015 at 11:33:36AM -0700, David G. Johnston wrote:
> On Sat, Apr 25, 2015 at 11:02 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>
> On Fri, Apr 24, 2015 at 08:40:40PM +0000, Kevin Grittner wrote:
> > And, for reasons given above, I really question whether such a
> > table doesn't do more harm than good.  Even those citing the paper
> > by Berenson, et al., often miss the text in *that* paper about what
> > the actual definition of serializable transactions in the standard
> > is, and instead focus on the quick-to-read tables of how the
> > misinterpretation of serializable transactions based on the
> > standard's table of phenomena (which the paper dubs "ANOMALY
> > SERIALIZABLE") differs from truly serializable behavior.
> >
> > People do love tables like this, which makes providing them
> > tempting; but when a short, clean table is available they often
> > seem less inclined to take the trouble to read the real information
> > the table summarizes -- and they come away with distorted and
> > incorrect ideas about the subject matter.
>
> I don't think we can abandon the table --- people have enough trouble
> figuring this out, including me, and without the table, it will be even
> harder.
>
> What I have done is to add two rows and one column to the table, and
> changed the surrounding text to more clearly reference the table.  You
> can see the output here, and the SGML patch is attached:
>
>         http://momjian.us/expire/transaction-iso.html
>
>
> Need to add "Serialization Anomalies" to the previous section's definitions
> list.

Uh, I am afraid the problem is that "Serialization Anomalies" is kind of
defined by the standard in an odd way that is specific to serializable
mode, I think. Kevin, is that true?

> ​Pondering whether something like: "Possible (not in PG)" and avoiding the
> additional rows would make reading the table easier.

Uh, that's an idea. I thought visually having two separate lines was
cleaner.

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

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