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Displaying 1-14 out of 14 total
Horton: Online Query Execution Engine for Large Distributed Graphs
Found in: Data Engineering, International Conference on
By Mohamed Sarwat,Sameh Elnikety,Yuxiong He,Gabriel Kliot
Issue Date:April 2012
pp. 1289-1292
Graphs are used in many large-scale applications, such as social networking. The management of these graphs poses new challenges as such graphs are too large for a single server to manage efficiently. Current distributed techniques such as map-reduce and P...
Clock-SI: Snapshot Isolation for Partitioned Data Stores Using Loosely Synchronized Clocks
Found in: 2013 IEEE 32nd International Symposium on Reliable Distributed Systems (SRDS)
By Jiaqing Du,Sameh Elnikety,Willy Zwaenepoel
Issue Date:September 2013
pp. 173-184
Clock-SI is a fully distributed protocol that implements snapshot isolation (SI) for partitioned data stores. It derives snapshot and commit timestamps from loosely synchronized clocks, rather than from a centralized timestamp authority as used in current ...
Tians Scheduling: Using Partial Processing in Best-Effort Applications
Found in: Distributed Computing Systems, International Conference on
By Yuxiong He, Sameh Elnikety, Hongyang Sun
Issue Date:June 2011
pp. 434-445
To service requests with high quality, interactive services such as web search, on-demand video and on line gaming keep average server utilization low. As servers become busy, queuing delays increase, and requests miss their deadlines, resulting in degrade...
One-copy serializability with snapshot isolation under the hood
Found in: Data Engineering, International Conference on
By Mihaela A. Bornea,Orion Hodson,Sameh Elnikety,Alan Fekete
Issue Date:April 2011
pp. 625-636
This paper presents a method that allows a replicated database system to provide a global isolation level stronger than the isolation level provided on each individual database replica. We propose a new multi-version concurrency control algorithm called, s...
Strongly consistent replication for a bargain
Found in: Data Engineering, International Conference on
By Konstantinos Krikellas, Sameh Elnikety, Zografoula Vagena, Orion Hodson
Issue Date:March 2010
pp. 52-63
Strong consistency is an important correctness property for replicated databases. It ensures that each transaction accesses the latest committed database state as provided in centralized databases. Achieving strong consistency in replicated databases is a ...
Database Replication Using Generalized Snapshot Isolation
Found in: Reliable Distributed Systems, IEEE Symposium on
By Sameh Elnikety, Willy Zwaenepoel, Fernando Pedone
Issue Date:October 2005
pp. 73-84
<p>Generalized snapshot isolation extends snapshot isolation as used in Oracle and other databases in a manner suitable for replicated databases. While (conventional) snapshot isolation requires that transactions observe the
Mars: Real-time spatio-temporal queries on microblogs
Found in: 2014 IEEE 30th International Conference on Data Engineering (ICDE)
By Amr Magdy,Ahmed M. Aly,Mohamed F. Mokbel,Sameh Elnikety,Yuxiong He,Suman Nath
Issue Date:March 2014
pp. 1238-1241
Mars demonstration exploits the microblogs location information to support a wide variety of important spatio-temporal queries on microblogs. Supported queries include range, nearest-neighbor, and aggregate queries. Mars works under a challenging environme...
Mercury: A memory-constrained spatio-temporal real-time search on microblogs
Found in: 2014 IEEE 30th International Conference on Data Engineering (ICDE)
By Amr Magdy,Mohamed F. Mokbel,Sameh Elnikety,Suman Nath,Yuxiong He
Issue Date:March 2014
pp. 172-183
This paper presents Mercury; a system for real-time support of top-k spatio-temporal queries on microblogs, where users are able to browse recent microblogs near their locations. With high arrival rates of microblogs, Mercury ensures real-time query respon...
QACO: exploiting partial execution in web servers
Found in: Proceedings of the 2013 ACM Cloud and Autonomic Computing Conference (CAC '13)
By Jinhan Kim, Sameh Elnikety, Seung-won Hwang, Shaolei Ren, Yuxiong He
Issue Date:August 2013
pp. 1-10
Web servers provide content to users, with the requirement of providing high response quality within a short response time. Meeting these requirements is challenging, especially in the event of load spikes. Meanwhile, we observe that a response to a reques...
Adaptive parallelism for web search
Found in: Proceedings of the 8th ACM European Conference on Computer Systems (EuroSys '13)
By Myeongjae Jeon, Sameh Elnikety, Scott Rixner
Issue Date:April 2013
pp. 155-168
A web search query made to Microsoft Bing is currently parallelized by distributing the query processing across many servers. Within each of these servers, the query is, however, processed sequentially. Although each server may be processing multiple queri...
G-SPARQL: a hybrid engine for querying large attributed graphs
Found in: Proceedings of the 21st ACM international conference on Information and knowledge management (CIKM '12)
By Sameh Elnikety, Sherif Sakr, Yuxiong He
Issue Date:October 2012
pp. 335-344
We propose a SPARQL-like language, G-SPARQL, for querying attributed graphs. The language expresses types of queries which of large interest for applications which model their data as large graphs such as: pattern matching, reachability and shortest path q...
Predicting replicated database scalability from standalone database profiling
Found in: Proceedings of the fourth ACM european conference on Computer systems (EuroSys '09)
By Emmanuel Cecchet, Sameh Elnikety, Steven Dropsho, Willy Zwaenepoel
Issue Date:April 2009
pp. 29-32
This paper develops analytical models to predict through-put and response time of a replicated database using meas-urements of the workload on a standalone database. These models allow workload scalability to be estimated before the replicated system is de...
Migrating server storage to SSDs: analysis of tradeoffs
Found in: Proceedings of the fourth ACM european conference on Computer systems (EuroSys '09)
By Antony Rowstron, Austin Donnelly, Dushyanth Narayanan, Eno Thereska, Sameh Elnikety
Issue Date:April 2009
pp. 29-32
Recently, flash-based solid-state drives (SSDs) have become standard options for laptop and desktop storage, but their impact on enterprise server storage has not been studied. Provisioning server storage is challenging. It requires optimizing for the perf...
Tashkent: uniting durability with transaction ordering for high-performance scalable database replication
Found in: Proceedings of the 2006 EuroSys conference (EuroSys '06)
By Fernando Pedone, Sameh Elnikety, Steven Dropsho
Issue Date:April 2006
pp. 2-es
In stand-alone databases, the functions of ordering the transaction commits and making the effects of transactions durable are performed in one single action, namely the writing of the commit record to disk. For efficiency many of these writes are grouped ...