May 28 – June 2 , 2017, Dagstuhl Seminar 17222

Robust Performance in Database Query Processing


Renata Borovica-Gajic (The University of Melbourne, AU)
Goetz Graefe (Google – Madison, US)
Allison Lee (Snowflake Computing Inc. – San Mateo, US)

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Dagstuhl Report, Volume 7, Issue 5 Dagstuhl Report
List of Participants
Shared Documents


The aim of this Dagstuhl Seminar on Robust Query Processing is to bring together top researchers from both industry and academia working on plan generation and plan execution in database query processing and in cloud-based massively parallel systems for data management. Delivering robust query performance is well known to be a difficult problem for database management systems. All experienced DBAs and database users are familiar with sudden disruptions in data centers due to poor performance of queries that have performed perfectly well in the past. The goal of the seminar is to discuss the current state-of-the-art, to identify specific research opportunities in order to improve the state-of-affairs in query processing, and to develop new approaches or even solutions for these opportunities.

Prior Dagstuhl Seminars have initiated discussions on robust performance of query processing in relational databases. They have proposed some metrics and benchmarks as well as initial solutions. These prior solutions have focused on data access, e.g., index scans vs. table scans as well as dynamic transitions from one to the other, and on execution algorithms, e.g., for joins and duplicate removal. Much work remains, e.g., on join sequences and on load balancing. It could be argued that the remaining work will be harder than the prior work – therefore, we invite to this Dagstuhl Seminar on Robust Query Processing.

The seminar will start with a focus on the problem and on prior results. Thereafter, seminar participants will work in small groups on specific problems. For example, one group might focus on detecting that a chosen join sequence is suboptimal for the actual predicate selectivities whereas another group might focus on changing dynamically the sequence of join and aggregation operations. Perhaps multiple groups focus on changing the join sequence assuming alternative join algorithms, e.g., order-based merge joins or order-agnostic hash joins. Interleaved plenary presentations and discussions will re-focus the working groups. Towards the end of the week, we may have concrete ideas for new techniques and perhaps for publications. Both academic and industrial participants may freely use the discussion contents and results for follow-on work.

  Creative Commons BY 3.0 DE
  Renata Borovica, Goetz Graefe, and Allison Lee

Dagstuhl Seminar Series


  • Data Bases / Information Retrieval


  • Database
  • Query processing
  • Query optimization
  • Query execution
  • Map-reduce
  • Systems
  • Cloud computing
  • Performance
  • Scalability
  • Robustness
  • Reliability
  • Predictability
  • Planning
  • Uncertainty

Book exhibition

Books from the participants of the current Seminar 

Book exhibition in the library, ground floor, during the seminar week.


In the series Dagstuhl Reports each Dagstuhl Seminar and Dagstuhl Perspectives Workshop is documented. The seminar organizers, in cooperation with the collector, prepare a report that includes contributions from the participants' talks together with a summary of the seminar.


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Furthermore, a comprehensive peer-reviewed collection of research papers can be published in the series Dagstuhl Follow-Ups.

Dagstuhl's Impact

Please inform us when a publication was published as a result from your seminar. These publications are listed in the category Dagstuhl's Impact and are presented on a special shelf on the ground floor of the library.

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