Re: "Priority Mechanisms for OLTP and Transactional Web Applications"

> -----Original Message-----
> From: harchol+(at)mor(dot)sync(dot)cs(dot)cmu(dot)edu
[mailto:harchol+(at)mor(dot)sync(dot)cs(dot)cmu(dot)edu]
> Sent: Wednesday, May 04, 2005 12:44 PM
> To: Dann Corbit
> Cc: cache+(at)cs(dot)cmu(dot)edu; harchol(at)cs(dot)cmu(dot)edu; natassa(at)cmu(dot)edu;
> bianca(at)cs(dot)cmu(dot)edu
> Subject: Re: "Priority Mechanisms for OLTP and Transactional Web
> Applications"
>
> Dear Dann,
>
> First of all, thank you for your interest in our work. We've
> got quite a few different priority implementations, based on our
> papers in: ICDE 2004, ICDE 2005, TOIT 2005, TOCS 2003, and some newly
> submitted papers that we just sent to VLDB 2005.
>
> Some of our most recent work, being led by my student Bianca
> Schroeder, deals with implementing the priority mechanism *externally*
> to the DBMS. The mechanism is a "black box" that sits between the web
> server and the DBMS and schedules which transactions are allowed to be
> sent into the DBMS and when. We find that this simple "external black
> box" achieves comparable results to scheduling internally to the DBMS
> and yet is far more portable, since it can work as a front-end to any
> DBMS.

This is (of course) a fascinating idea, and will be generally useful for
any sort of database implementation. Since you are using a JDBC
interface and manipulation the Java calls, there is no need to consider
modifications to the PostgreSQL database [or any other] in such a
circumstance. It does make an interesting study, and I think it may be
even more interesting to see if both approaches can work together.

However, the internal modifications are of more immediate interest to
me, since it allows a simple way to achieve the benefits regardless of
the interface method chosen.

> If you are interested in the most recent "external approach" described
> above, please let me know and I will gladly forward to you our recent
> proposal on this idea and some papers in submission.

I have seen and downloaded some of the papers from your web site.

> All our earlier work deals with "internal scheduling approaches"
> (scheduling *within* the DBMS or the OS). The relevant papers there
> can be found on my web page or that of my students, and David
> McWherter would be happy to help answer questions on implementation.

I have contacted Mr. McWherter and he seems to have some interest in
helping.

Thank you for your quick and helpful reply.

> With best regards,
> Mor
>
> P.S. I didn't cc to "pgsql-hackers(at)postgresql(dot)org" since I wasn't
> sure how far that list extended and didn't want to SPAM folks, but
> feel free to pass on the above message if you think it's relevant
> to these folks.
>
> -------------------------------
> Mor Harchol-Balter
> Associate Professor
> Computer Science Dept
> Carnegie Mellon University
> 5000 Forbes Ave.
> Pittsburgh, PA 15213-3891
>
> WEB: www.cs.cmu.edu/~harchol
> Email: harchol(at)cs(dot)cmu(dot)edu
> Phone: (412) 268-7893
> Fax: (412) 268-5576
> Assistant: Charlotte Yano
> yano(at)cs(dot)cmu(dot)edu
> -------------------------------