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Concept

Sort-merge join

Publications associées (14)

Efficient Massively Parallel Join Optimization for Large Queries

Anastasia Ailamaki, Bikash Chandra, Srinivas Karthik Venkatesh

Modern data analytical workloads often need to run queries over a large number of tables. An optimal query plan for such queries is crucial for being able to run these queries within acceptable time bounds. However, with queries involving many tables, find ...

ACM2022

Bridging the Latency Gap between NVM and DRAM for Latency-bound Operations

Anastasia Ailamaki, Georgios Psaropoulos

Non-Volatile Memory (NVM) technologies exhibit 4× the read access latency of conventional DRAM. When the working set does not fit in the processor cache, this latency gap between DRAM and NVM leads to more than 2× runtime increase for queries dominated by ...

ACM2019

Improving Main-memory Database System Performance through Cooperative Multitasking

Georgios Psaropoulos

Database systems access memory either sequentially or randomly. Contrary to sequential access and despite the extensive efforts of computer architects, compiler writers, and system builders, random access to data larger than the processor cache has been s ...

EPFL2019

Time- and Space-Efficient Spatial Data Analytics

Mirjana Pavlovic

Advances in data acquisition technologies and supercomputing for large-scale simulations have led to an exponential growth in the volume of spatial data. This growth is accompanied by an increase in data complexity, such as spatial density, but also by mor ...

EPFL2019

Hardware-conscious Hash-Joins on GPUs

Anastasia Ailamaki, Raja Appuswamy, Manolis Karpathiotakis, Periklis Chrysogelos, Panagiotis Sioulas

Traditionally, analytical database engines have used task parallelism provided by modern multisocket multicore CPUs for scaling query execution. Over the past few years, GPUs have started gaining traction as accelerators for processing analytical queries d ...

IEEE2019

Interleaving with coroutines: a systematic and practical approach to hide memory latency in index joins

Anastasia Ailamaki, Georgios Psaropoulos

Index joins present a case of pointer-chasing code that causes data cache misses. In principle, we can hide these cache misses by overlapping them with computation: The lookups involved in an index join are parallel tasks whose execution can be interleaved ...

2019

A Framework Based on Predictive Maintenance, Zero-Defect Manufacturing and Scheduling Under Uncertainty Tools, to Optimize Production Capacities of High-End Quality Products

Dimitrios Kyritsis

Nowadays exploiting the full potential of the humongous amount of data that manufactures can produce with their production means is a real challenge. Moreover, increasing production capabilities without large investments is a recurring objective for them. ...

SPRINGER-VERLAG BERLIN2018

Interleaving with Coroutines: A Practical Approach for Robust Index Joins

Anastasia Ailamaki, Georgios Psaropoulos

Index join performance is determined by the efficiency of the lookup operation on the involved index. Although database indexes are highly optimized to leverage processor caches, main memory accesses inevitably increase lookup runtime when the index outsiz ...

VLDB Endowment Inc.2017

Squall: Scalable Real-time Analytics

Christoph Koch, Mohammad Dashti Rahmat Abadi, Ioannis Klonatos, Aleksandar Vitorovic, Mohamed Elsayed Mohamed Ahmed El Seidy, Minh Khue Vu

Squall is a scalable online query engine that runs complex analytics in a cluster using skew-resilient, adaptive operators. Squall builds on state-of-the-art partitioning schemes and local algorithms, including some of our own. This paper presents the over ...

VLDB Endowment Inc.2016

Squall: Scalable Real-time Analytics using Efficient, Skew-resilient Join Operators

Aleksandar Vitorovic

Squall is a scalable online query engine that runs complex analytics in a cluster using skew-resilient, adaptive operators. Online processing implies that results are incrementally built as the input arrives, and it is ubiquitous for many applications such ...

EPFL2023

TOUCH: In-Memory Spatial Join by Hierarchical Data-Oriented Partitioning

Anastasia Ailamaki, Thomas Heinis, Farhan Tauheed

Efficient spatial joins are pivotal for many applications and particularly important for geographical information systems or for the simulation sciences where scientists work with spatial models. Past research has primarily focused on disk-based spatial jo ...

2013

Generalized Hypertree Decompositions: NP-hardness and Tractable Variants

Zoltán Miklós

The generalized hypertree width GHW(H) of a hypergraph H is a measure of its cyclicity. Classes of conjunctive queries or constraint satisfaction problems whose associated hypergraphs have bounded GHW are known to be solvable in polynomial time. However, i ...

2009

Implementing Joins using Extensible Pattern Matching

Philipp Haller

Join patterns are an attractive declarative way to synchronize both threads and asynchronous distributed computations. We explore joins in the context of extensible pattern matching that recently appeared in languages such as F# and Scala. Our implementati ...

Springer2008

Subjective Evaluation of Join Cost and Smoothing Methods for Unit Selection Speech Synthesis

In unit selection-based concatenative speech synthesis, join cost (also known as concatenation cost), which measures how well two units can be joined together, is one of the main criteria for selecting appropriate units from the inventory. Usually, some fo ...

2006