Re: Major features for 9.1 - Mailing list pgsql-advocacy

Yes, SSI confuses me too. I used to use server sides includes in the eve
of web. I think our SSI is a cool technology and wiki page is must to have.
But I'd like to see useful examples.

Oleg

On Mon, 4 Apr 2011, Kevin Grittner wrote:

> Jeff Davis <pgsql@j-davis.com> wrote:
>> On Mon, 2011-04-04 at 07:20 -0500, Kevin Grittner wrote:
>>>> a) a two-line explanation of what the feature is and why it's
>>>> valuable (for the release notes, etc.)
>>>> b) a wiki page with a more detailed explaination and examples
>>>> oriented towards the beginning-to-intermediate PostgreSQL user.
>>>>
>>>> Volunteers?
>>>
>>> I volunteer for SSI.
>>
>> The way I think about SSI is that it automatically detects live
>> race conditions in your SQL transactions at runtime; and protects
>> you by safely rolling some of them back (which can be retried
>> safely).
>>
>> Maybe something along those lines?
>
> That is very accessible to an IT manager who's not a database
> expert, and conceptually very clean.  It doesn't directly address
> what's innovative about it, though, nor does it directly address why
> it's valuable -- although one could infer both through a close
> reading.
>
> To extend that such that the innovative nature and benefits are more
> explicitly stated, perhaps:
>
> SSI allows you to enforce arbitrarily complex user-defined business
> rules within the database without blocking, by automatically
> detecting live race conditions in your SQL transactions at runtime.
> It protects you by safely rolling some of them back (which can be
> retried safely).
>
> It's more than two lines, but I'm not immediately able to see what
> to cut.
>
> By the way, I did some google searches to try to find a prior
> production quality implementation, and have so far not found any.  I
> have discovered that SSI is a very popular TLA, including its use
> for something called Server Side Includes (SSI.php) which is a
> popular enough technology with databases for people to be listing
> years of experience with it on their LinkedIn pages.  I don't know
> how much of a problem that might be.  I guess at a minimum we should
> add Serializable Snapshot Isolation to the Wikipedia SSI page:
>
> http://en.wikipedia.org/wiki/SSI
>
> Maybe we shouldn't use SSI without spelling out Serializable
> Snapshot Isolation, to avoid confusion.
>
> -Kevin
>
>

     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83