Publications de Sameh Mohamed Elnikety

PerfIso: Performance Isolation for Commercial Latency-Sensitive Services

Sameh Mohamed Elnikety, Calin Iorgulescu

Large commercial latency-sensitive services, such as web search, run on dedicated clusters provisioned for peak load to ensure responsiveness and tolerate data center outages. As a result, the average load is far lower than the peak load used for provision ...

The USENIX Association2018

PerfIso: Performance Isolation for Commercial Latency-Sensitive Services

Sameh Mohamed Elnikety, Calin Iorgulescu

Large commercial latency-sensitive services, such as web search, run on dedicated clusters provisioned for peak load to ensure responsiveness and tolerate data center outages. As a result, the average load is far lower than the peak load used for provision ...

USENIX ASSOC2018

Clock-RSM: Low-Latency Inter-Datacenter State Machine Replication Using Loosely Synchronized Physical Clocks

Fernando Pedone, Willy Zwaenepoel, Sameh Mohamed Elnikety, Jiaqing Du

2014

Orbe: Scalable Causal Consistency Using Dependency Matrices and Physical Clocks

Willy Zwaenepoel, Sameh Mohamed Elnikety, Jiaqing Du, Amitabha Roy

We propose two protocols that provide scalable causal consistency for both partitioned and replicated data stores using dependency matrices (DM) and physical clocks. The DM protocol supports basic read and update operations and uses two-dimensional depende ...

2013

Clock-SI: Snapshot Isolation for Partitioned Data Stores Using Loosely Synchronized Clocks

Willy Zwaenepoel, Sameh Mohamed Elnikety, Jiaqing Du

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 ...

2013

Predicting Replicated Database Scalability from Standalone Database Profiling

Willy Zwaenepoel, Sameh Mohamed Elnikety, Emmanuel Cecchet

This paper develops analytical models to predict the throughput and the response time of a replicated database using measurements of the workload on a standalone database. These models allow workload scalability to be estimated before the replicated system ...

2009

Transparent scalable database replication

Sameh Mohamed Elnikety

This thesis demonstrates that, despite earlier projections to the contrary, database replication on a cluster of low-cost commodity servers can transparently scale database performance. In a replicated system providing the standard transactional properties ...

EPFL2008

Tashkent+: Memory-Aware Load Balancing and Update Filtering in Replicated Databases

Willy Zwaenepoel, Sameh Mohamed Elnikety

BEST PAPER AWARDWe present a memory-aware load balancing (MALB) technique to dispatch transactions to replicas in a replicated database. Our MALB algorithm exploits knowledge of the working sets of transactions to ...

2007

Tashkent: Uniting Durability with Transaction Ordering for High-Performance Scalable Database Replication

Fernando Pedone, Sameh Mohamed Elnikety

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 ...

2006

Database Replication Using Generalized Snapshot Isolation

Fernando Pedone, Willy Zwaenepoel, Sameh Mohamed Elnikety

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 “latest” snapshot of the database, ...

2005