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Record W4413980865 · doi:10.14778/3749646.3749703

Sphinx: A Succinct Perfect Hash Index for x86

2025· article· en· W4413980865 on OpenAlexaff
Sajad Faghfoor Maghrebi, Niv Dayan

Bibliographic record

VenueProceedings of the VLDB Endowment · 2025
Typearticle
Languageen
FieldComputer Science
TopicAdvanced Data Storage Technologies
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsHash functionSphinxIndex (typography)Computer sciencex86Computer securityHistoryWorld Wide WebProgramming languageArchaeology

Abstract

fetched live from OpenAlex

Many modern key-value stores rely on an in-memory index to map the location of each data entry in storage. The size of this index often becomes a memory bottleneck that makes it difficult to scale the system to large data sizes. To address this problem, the state-of-the-art approach is to structure this index as a succinct perfect hash table using only ≈ 4 bits per key. The downside is that the hash table encoding is computationally expensive to parse and may harm overall system performance. We introduce Sphinx, a succinct perfect hash table reengineered for high performance on commodity CPUs. Sphinx is encoded in a manner that lends itself to efficient access using rank and select primitives, and it uses auxiliary metadata to decode common hash table slots instantaneously. Sphinx is also expandable and parallelizable. We compare Sphinx to the best alternatives and show that it leads to a 2x reduction in query latency, update latency, and memory footprint.

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.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.010
Threshold uncertainty score0.033

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0010.001
Science and technology studies0.0010.001
Scholarly communication0.0010.003
Open science0.0020.002
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0100.005

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 head0.009
GPT teacher head0.249
Teacher spread0.239 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
Domainnot available
GenreMethods

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations2
Published2025
Admission routes1
Has abstractyes

Explore more

Same venueProceedings of the VLDB EndowmentSame topicAdvanced Data Storage TechnologiesFrench-language works237,207