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Methods and Apparatus for Throttling and Reordering Database Requests

IP.com Disclosure Number: IPCOM000018769D
Original Publication Date: 2003-Aug-07
Included in the Prior Art Database: 2003-Aug-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Abstract

Methods and Apparatus for Throttling and Reordering Database Requests

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Methods and Apparatus for Throttling and Reordering Database Requests

Methods and Apparatus for Throttling and Reordering Database Requests

Sameh M. Elnikety, Erich M. Nahum, John M. Tracey

Database performance can be characterized by two parameters, throughput and latency. Both can suffer dramatically when the database is overloaded. Consider a database that can sustain a maximum throughput of X queries per second. Presume that, at this maximum load, the database completes each query in Y milliseconds on average. If the database is subjected to an offered load greater than X, it will typically complete far fewer than X queries per second and each query will typically take longer than Y milliseconds to complete.

Our invention improves database performance in terms of throughput during overload conditions and in terms of latency regardless of overload. These effects are achieved via two mechanisms: throttling and reordering. Throttling of queries allows the database to sustain peak performance under overload conditions. Reordering short queries ahead of long ones improves average response time.

The invention consists of four essential components and one optional component. The four essential components are:

1) A mechanism to classify each query according to its type.
2) Mechanisms to measure the resource utilization or requirements for each type of query.
3) A mechanism to estimate the maximum capacity of the database.
4) A mechanism to throttle queries to the database based on resource requirements to prevent overload.

Optionally, the invention can be deployed with a fifth component.

5) A mechanism to reorder queries to the database to favor requests with low resource requirements thus improving response time.

The invention classifies each query based...