CS848 Paper Review Form - Fall 2006

Paper Title: Relaxed Currency and Consistency: How to 
 Say "Good Enough" in SQL

Author(s):

1) Is the paper technically correct?
 [X] Yes
 [ ] Mostly (minor flaws, but mostly solid)
 [ ] No

2) Originality
 [ ] Very good (very novel, trailblazing work)
 [X] Good 
 [ ] Marginal (very incremental)
 [ ] Poor (little or nothing that is new)

3) Technical Depth
 [ ] Very good (comparable to best conference papers)
 [X] Good (comparable to typical conference papers)
 [ ] Marginal depth
 [ ] Little or no depth

4) Impact/Significance
 [ ] Very significant
 [X] Significant
 [ ] Marginal significance.
 [ ] Little or no significance.

5) Presentation
 [ ] Very well written
 [X] Generally well written
 [ ] Readable
 [ ] Needs considerable work
 [ ] Unacceptably bad

6) Overall Rating
 [ ] Strong accept (very high quality)
 [X] Accept (high quality - would argue for acceptance)
 [ ] Weak Accept (marginal, willing to accept but wouldn't argue for it)
 [ ] Weak Reject (marginal, probably reject)
 [ ] Reject (would argue for rejection)

7) Summary of the paper's main contribution and rationale
   for your recommendation. (1-2 paragraphs)

This paper defines syntax and semantics for consistency and
freshness requirements on SQL queries.  It also presents
a mechanism implemented in MTCache, a mid-tier database caching
system, that ensures that such requirements are satisfied.
The paper presents empirical results that suggest that the
enforcement overhead is not high, and that illustrate how
freshness and consistency requirements affect ability of
the mid-tier cache to absorb workload.

The requirements are novel, useful, and clearly defined
and illustrated.  The implementation is also clear and elegant,
and the paper does a nice job of illustrating some of
the query evaluation tradeoffs through examples.
Solid and interesting work.


8) List 1-3 strengths of the paper.  (1-2 sentences each,
identified as S1, S2, S3.)

S1: The integration of freshness and consistency constraints
  into a cost-based optimizer.

S2: The paper is generally well-written, and makes good 
  use of examples. 


9) List 1-3 weaknesses of the paper (1-2 sentences each,
identified as W1, W2, W3.)

W1: The semantics of consistency and freshness constraints
  for multi-block queries is unclear.


10) Detailed comments for authors.

* What the paper calls "currency" increases as a view
  becomes more out of date.  "Staleness" would have
  been a better word for this concept.

* According to the paper, each materialized view belongs
  to a consistency region.  What about base tables?  Do
  those also belong to consistency regions?
  Some query evaluation plans will involve base tables,
  and in order for the "delivered consistency properties"
  (Section 3.2.2) to be determined for those plans, it
  would seem that base tables must also be associated
  with a consistency region.