A Practical Approach to Groupjoin and Nested Aggregates

Summary: Addresses groupjoins and nested aggregates with aggregate estimates that predict post-aggregation distributions for better optimization. Introduces contention-free parallel groupjoin execution, improving many-core scalability and accelerating some TPC-H queries up to 2×. (summarized by gpt-5.6-luna on Jul 24 2026)

Paper ID: hf18391b5cf596269
Venue: VLDB
Year: 2021
Pagerank: 5.4082473e-05
Overall Rank: 7,927 | 46.87%
DOI: 10.14778/3476249.3476288
PDF: Download (CC BY-NC-ND 4.0)

Incoming Non-self Citations Over Time

Authors

1. Philipp Fent (Technical University of Munich)
2. Thomas Neumann (Technical University of Munich)

BibTeX Citation

@article{fent_vldb21,
        title = {{A Practical Approach to Groupjoin and Nested Aggregates}},
        author = {Fent, Philipp and Neumann, Thomas},
        journal = {PVLDB},
        series = {{VLDB} '21},
        volume = {14},
        number = {11},
        pages = {2383--2396},
        doi = {10.14778/3476249.3476288},
        url = {https://doi.org/10.14778/3476249.3476288},
        year = {2021}
}

Incoming Citations (Sorted by Pagerank)

Showing 6 of 6 citing papers.

Rank	Citing Paper	Year	Venue	Pagerank
5,787	Database Technology for the Masses: Sub-Operators as First-Class Entities	2021	VLDB	5.9768075e-05
7,373	A Scalable and Generic Approach to Range Joins	2022	VLDB	5.5245298e-05
9,594	Global Hash Tables Strike Back! An Analysis of Parallel GROUP BY Aggregation	2026	VLDB	5.1376962e-05
10,581	SPALM: A Sparsity-Pattern-Adaptive Library for Matrices	2026	SIGMOD	4.9605343e-05
11,353	Cardinality Estimation for Having-Clauses	2025	VLDB	4.9605343e-05
13,701	UmbraPerf - Profiling Results Tailored for DBMS Developers	2025	VLDB	-

Outgoing Citations (Sorted by Pagerank)

Showing 39 of 39 cited papers.

Citations counted here include only citations to other VLDB/SIGMOD/CIDR/PODS papers in this database.

Rank	Cited Paper	Year	Venue	Pagerank
14	MonetDB/X100: Hyper-Pipelining Query Execution	2005	CIDR	0.00063972112
15	How Good Are Query Optimizers, Really?	2016	VLDB	0.00061463175
21	Efficiently Compiling Efficient Query Plans for Modern Hardware	2011	VLDB	0.00056737487
34	The Design Of Postgres	1986	SIGMOD	0.00049063803
84	Learned Cardinalities: Estimating Correlated Joins with Deep Learning	2019	CIDR	0.00035920657
99	Of Nests and Trees: A Unified Approach to Processing Queries That Contain Nested Subqueries, Aggregates, and Quantifiers	1987	VLDB	0.00034024478
106	Quickly Generating Billion-Record Synthetic Databases	1994	SIGMOD	0.00033563032
161	DB2 with BLU Acceleration: So Much More than Just a Column Store	2013	VLDB	0.00027629724
212	Sort vs. Hash Revisited: Fast Join Implementation on Modern Multi-Core CPUs	2009	VLDB	0.00024786576
213	Eager Aggregation and Lazy Aggregation	1995	VLDB	0.00024695393
215	Morsel-Driven Parallelism: A NUMA-Aware Query Evaluation Framework for the Many-Core Age	2014	SIGMOD	0.00024554257
320	DeepDB: Learn from Data, not from Queries!	2020	VLDB	0.00021128745
375	Umbra: A Disk-Based System with In-Memory Performance	2020	CIDR	0.00019660459
381	Preventing Bad Plans by Bounding the Impact of Cardinality Estimation Errors	2009	VLDB	0.00019497061
473	The Making of TPC-DS	2006	VLDB	0.00017656775
554	Orthogonal Optimization of Subqueries and Aggregation	2001	SIGMOD	0.00016487919
626	Adaptive Aggregation on Chip Multiprocessors	2007	VLDB	0.00015431379
690	Selectivity Estimation for Range Predicates using Lightweight Models	2019	VLDB	0.00014703258
841	Quickr: Lazily Approximating Complex AdHoc Queries in BigData Clusters	2016	SIGMOD	0.00013503124
1,015	Improved Unnesting Algorithms for Join Aggregate SQL Queries	1992	VLDB	0.00012468327
1,032	Cost-Based Optimization for Magic: Algebra and Implementation	1996	SIGMOD	0.00012376627
1,269	An Experimental Comparison of Thirteen Relational Equi-Joins in Main Memory	2016	SIGMOD	0.00011236561
1,350	Relaxed Operator Fusion for In-Memory Databases: Making Compilation, Vectorization, and Prefetching Work Together At Last	2018	VLDB	0.00010934877
1,381	Execution Strategies for SQL Subqueries	2007	SIGMOD	0.00010832197
1,958	Quantifying TPC-H Choke Points and Their Optimizations	2020	VLDB	9.2894133e-05
2,122	Enhanced Subquery Optimizations in Oracle	2009	VLDB	8.9938885e-05
2,661	A Robust, Optimization-Based Approach for Approximate Answering of Aggregate Queries	2001	SIGMOD	8.1414177e-05
2,673	A Layered Aggregate Engine for Analytics Workloads	2019	SIGMOD	8.1276375e-05
2,827	To Partition, or Not to Partition, That is the Join Question in a Real System	2021	SIGMOD	7.9486247e-05
3,136	Every Row Counts: Combining Sketches and Sampling for Accurate Group-By Result Estimates	2019	CIDR	7.5902303e-05
4,227	Accelerating Queries with Group-By and Join by Groupjoin	2011	VLDB	6.7087461e-05
4,815	Error-bounded Sampling for Analytics on Big Sparse Data	2014	VLDB	6.3890155e-05
5,611	StatAdvisor: Recommending Statistical Views	2009	VLDB	6.0498181e-05
6,228	Data Partitioning for In-Memory Systems: Myths, Challenges, and Opportunities	2019	CIDR	5.8261473e-05
7,319	Optimization of Nested Queries using the NF2 Algebra	2016	SIGMOD	5.5410915e-05
7,495	PgCuckoo: Laying Plan Eggs in PostgreSQL's Nest	2019	SIGMOD	5.4972537e-05
7,887	Building Advanced SQL Analytics From Low-Level Plan Operators	2021	SIGMOD	5.4162508e-05
9,249	Chasing Similarity: Distribution-aware Aggregation Scheduling	2019	VLDB	5.1860134e-05
10,226	Bridging the Chasm between Science and Reality	2021	CIDR	5.0450381e-05

Semantically Similar Papers

#	Overall Rank	Paper	Year	Venue
1	1,633	Adaptive Parallel Aggregation Algorithms	1995	SIGMOD
2	13,065	A Nested Relational Approach to Processing SQL Subqueries	2005	SIGMOD
3	9,594	Global Hash Tables Strike Back! An Analysis of Parallel GROUP BY Aggregation	2026	VLDB
4	1,015	Improved Unnesting Algorithms for Join Aggregate SQL Queries	1992	VLDB
5	1,296	From Theory to Practice: Efficient Join Query Evaluation in a Parallel Database System	2015	SIGMOD
6	554	Orthogonal Optimization of Subqueries and Aggregation	2001	SIGMOD
7	5,721	Efficiently Processing Joins and Grouped Aggregations on GPUs	2025	SIGMOD
8	73	Including Group-By in Query Optimization	1994	VLDB
9	11,670	Grouping, Subsumption, and Disjunctive Join Optimizations in Oracle	2024	VLDB
10	4,227	Accelerating Queries with Group-By and Join by Groupjoin	2011	VLDB