Schedule - pgDay Paris 2017

Measuring and Reducing PostgreSQL Transaction Latency

Date: 2017-03-23
Time: 12:05–12:55
Room: Auditorium
Level: Beginner

Database performance is often measured as the maximal transaction throughput, typically reported by benchmarks as an average number of transactions-per-second (tps). We show that using this as the only measure of performance can lead to unexpected or even detrimental behaviors when one gets a closer look at what is happening. We argue that latency (the time to process a transaction, typically in ms), for a database engine not necessarily running at maximal throughput, must be considered: think for instance of a responsive web application which consults and updates a database. We then analyze the path of a transaction to explain its latency, and then discuss how to reduce this latency of database transactions as seen from the client application, using obvious and possibly less obvious tricks.


Fabien Coelho