28,311 research outputs found
Middleware-based Database Replication: The Gaps between Theory and Practice
The need for high availability and performance in data management systems has
been fueling a long running interest in database replication from both academia
and industry. However, academic groups often attack replication problems in
isolation, overlooking the need for completeness in their solutions, while
commercial teams take a holistic approach that often misses opportunities for
fundamental innovation. This has created over time a gap between academic
research and industrial practice.
This paper aims to characterize the gap along three axes: performance,
availability, and administration. We build on our own experience developing and
deploying replication systems in commercial and academic settings, as well as
on a large body of prior related work. We sift through representative examples
from the last decade of open-source, academic, and commercial database
replication systems and combine this material with case studies from real
systems deployed at Fortune 500 customers. We propose two agendas, one for
academic research and one for industrial R&D, which we believe can bridge the
gap within 5-10 years. This way, we hope to both motivate and help researchers
in making the theory and practice of middleware-based database replication more
relevant to each other.Comment: 14 pages. Appears in Proc. ACM SIGMOD International Conference on
Management of Data, Vancouver, Canada, June 200
Recommended from our members
Fault diversity among off-the-shelf SQL database servers
Fault tolerance is often the only viable way of obtaining the required system dependability from systems built out of "off-the-shelf" (OTS) products. We have studied a sample of bug reports from four off-the-shelf SQL servers so as to estimate the possible advantages of software fault tolerance - in the form of modular redundancy with diversity - in complex off-the-shelf software. We checked whether these bugs would cause coincident failures in more than one of the servers. We found that very few bugs affected two of the four servers, and none caused failures in more than two. We also found that only four of these bugs would cause identical, undetectable failures in two servers. Therefore, a fault-tolerant server, built with diverse off-the-shelf servers, seems to have a good chance of delivering improvements in availability and failure rates compared with the individual off-the-shelf servers or their replicated, nondiverse configurations
Atomic commitment in transactional DHTs
We investigate the problem of atomic commit in transactional database systems
built on top of Distributed Hash Tables. DHTs provide a decentralized way to
store and look up data. To solve the atomic commit problem we propose to
use an adaption of Paxos commit as a non-blocking algorithm. We exploit the
symmetric replication technique existing in the DKS DHT to determine which
nodes are necessary to execute the commit algorithm. By doing so we achieve a
lower number of communication rounds and a reduction of meta-data in contrast
to traditional Three-Phase-Commit protocols. We also show how the proposed
solution can cope with dynamism due to churn in DHTs. Our solution works
correctly relying only on an inaccurate failure detection of node failure which is
necessary for systems running over the Internet
- …