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Record W2950833175 · doi:10.1145/3299869.3319894

Pessimistic Cardinality Estimation

2019· article· en· W2950833175 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

fundA Canadian funder is recorded on the work.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldComputer Science
TopicData Management and Algorithms
Canadian institutionsnot available
FundersAlberta Innovates - Technology FuturesNational Science Foundation
KeywordsComputer scienceCardinality (data modeling)Benchmark (surveying)Hash functionTupleKey (lock)Monotonic functionParameterized complexityPartition (number theory)Join (topology)Theoretical computer scienceMathematical optimizationAlgorithmData miningMathematicsDiscrete mathematics

Abstract

fetched live from OpenAlex

In this work we introduce a novel approach to the problem of cardinality estimation over multijoin queries. Our approach leveraging randomized hashing and data sketching to tighten these bounds beyond the current state of the art. We demonstrate that the bounds can be injected directly into the cost based query optimizer framework enabling it to avoid expensive physical join plans. We outline our base data structures and methodology, and how these bounds may be introduced to the optimizer's parameterized cost function as a new statistic for physical join plan selection. We demonstrate a complex tradeoff space between the tightness of our bounds and the size and complexity of our data structures. This space is not always monotonic as one might expect. In order combat this non-monotonicity, we introduce a partition budgeting scheme that guarantees monotonic behavior. We evaluate our methods on GooglePlus community graphs~\citegoogleplus, and the Join Order Benchmark (JOB)~\citeLeis:2015:GQO:2850583.2850594. In the presence of foreign key indexes, we demonstrate a $1.7\times$ improvement in aggregate (time summed over all queries in benchmark) physical query plan runtime compared to plans chosen by Postgres using the default cardinality estimation methods. When foreign key indexes are absent, this advantage improves to over $10\times$.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: none
Teacher disagreement score0.972
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.001
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.008
GPT teacher head0.227
Teacher spread0.219 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Quick stats

Citations77
Published2019
Admission routes1
Has abstractyes

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