Past Meetup

A Critique of ANSI SQL Isolation Levels

This Meetup is past

15 people went


Nobelstraat 2A · Utrecht

How to find us

Use the bottom doorbell ("Rentman/ProductImpulse"). Follow the signs and find us on the second floor.

Location image of event venue


Crazy about concurrency, and love some linearizability? Then this edition of Papers We Love is something that should get you excited! Marco Rietveld will discuss all things ACID to give you a solid BASE of understanding about single node database systems.

Find the paper here (


A Critique of ANSI SQL Isolation Levels


ANSI SQL-92 defines Isolation Levels in terms of phenomena: Dirty Reads, Non-Repeatable Reads, and Phantoms. This paper shows that these phenomena and the ANSI SQL definitions fail to characterize several popular isolation levels, including the standard locking implementations of the levels. Investigating the ambiguities of the phenomena leads to clearer definitions; in addition new phenomena that better characterize isolation types are introduced. An important multiversion isolation type, Snapshot Isolation, is defined.

Target audience

The presentation is intended for those who understand the concepts of threads, transactions, concurrency and databases. The motivation behind the talk is to provide the basis necessary for understanding the challenges in heavy-load systems as well as systems involving parallel data storage.

Speaker: Marco Rietveld

Marco has been working as a Java software engineer for the last 8 years, most recently as a core developer on the jBPM/Drools project where he focused on persistence, core (BPM) engine and serialization issues as well as the REST API. At the moment, he is currently taking a sabbatical in order to improve his technical knowledge and skills. Before working as a software engineer, he has worked as both an information analyst at Schiphol and as well as a Linux/Unix systems administrator.

You can find Marco on GitHub at


This edition of Papers We Love Utrecht is made possible by the lovely folks at Channable ( We want to thank them for providing us with the space, food and drinks we need to make this edition a reality.


19:00 - Welcome with food and drinks
19:30 - Talk + Discussion
20:00 - Announcements
21:00 - Fin

Getting to the location

Channable's office is located next to the Janskerkhof. You can find the front door between Ludwig Coffee Bar and The Florin. Look out for the Papers We Love sign. Use the bottom doorbell ("Rentman/ProductImpulse") if the door is closed. Find us on the second floor.


The location is in the center of Utrecht. Therefore, parking options are limited. You can try your luck here:

Keizerstraat[masked] EA Utrecht

If full, there is a proper parking garage within a 10 minute walk of the Channable office:

Kruisstraat[masked] GK Utrecht