Database index

A database index is a data structure that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space to maintain the index data structure. Indexes are used to quickly locate data without having to search every row in a database table every time said table is accessed. Indexes can be created using one or more columns of a database table, providing the basis for both rapid random lookups and efficient access of ordered records. An index is a copy of selected columns of data, from a table, that is designed to enable very efficient search. An index normally includes a "key" or direct link to the original row of data from which it was copied, to allow the complete row to be retrieved efficiently. Some databases extend the power of indexing by letting developers create indexes on column values that have been transformed by functions or expressions. For example, an index could be created on upper(last_name), which would only st

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In computing, a database is an organized collection of data (also known as a data store) stored and accessed electronically through the use of a database management system. Small databases can be st

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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 outsizes the last-level cache; hence, index join performance drops. Still, robust index join performance becomes possible with instruction stream interleaving: given a group of lookups, we can hide cache misses in one lookup with instructions from other lookups by switching among their respective instruction streams upon a cache miss. In this paper, we propose interleaving with coroutines for any type of index join. We showcase our proposal on SAP HANA by implementing binary search and CSB+-tree traversal for an instance of index join related to dictionary compression. Coroutine implementations not only perform similarly to prior interleaving techniques, but also resemble the original code closely, while supporting both interleaved and non-interleaved execution. Thus, we claim that coroutines make interleaving practical for use in real DBMS codebases.

VLDB Endowment Inc.2017

Dark Silicon Accelerators for Database Indexing

Babak Falsafi, Yusuf Onur Koçberber

2012

Dark Silicon Accelerators for Database Indexing

Babak Falsafi, Yusuf Onur Koçberber

The growing explosion of digital data motivates renewed emphasis on new architectures for future data-centric workloads. At the same time, the inability of power to scale with increasing transistor counts has led to a recent focus on “dark silicon” designs where transistors are used to design specialized accelerators to improve energy efficiency and performance. Combining these trends, in this paper, we examine the applicability of accelerators in future data-centric system architectures. Specifically, we focus on indexing, a fundamental and time consuming component of databases, and propose a new “indexing widget” to improve energy efficiency and performance. Through preliminary characterization of a representative scale-out database, VoltDB, in conjunction with performance, power and area models, we show that our proposed approach can achieve 1.24X improvement in energy efficiency relative to non-accelerated designs.

2012

In computing, a database is an organized collection of data (also known as a data store) stored and accessed electronically through the use of a database management system. Small databases can be st

A relational database is a (most commonly digital) database based on the relational model of data, as proposed by E. F. Codd in 1970. A system used to maintain relational databases