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Main Authors: Gammell, Jimmy, Thapaliya, Bishal, Jung, Yoon, Ohib, Riyasat, Fehri, Bilel, Chakrabarti, Deepayan
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.07027
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author Gammell, Jimmy
Thapaliya, Bishal
Jung, Yoon
Ohib, Riyasat
Fehri, Bilel
Chakrabarti, Deepayan
author_facet Gammell, Jimmy
Thapaliya, Bishal
Jung, Yoon
Ohib, Riyasat
Fehri, Bilel
Chakrabarti, Deepayan
contents Nonstationarity is ubiquitous in practical classification settings, leading deployed models to perform poorly even when they generalize well to holdout sets available at training time. We address this by reframing nonstationary classification as time series prediction: rather than predicting from the current input alone, we condition the classifier on a sequence of historical labeled examples that extends beyond the training cutoff. To scale to large sequences, we introduce a learned discrete retrieval mechanism that samples relevant historical examples via input-dependent queries, trained end-to-end with the classifier using a score-based gradient estimator. This enables the full corpus of historical data to remain on an arbitrary filesystem during training and deployment. Experiments on synthetic benchmarks and Amazon Reviews '23 (electronics category) show improved robustness to distribution shift compared to standard classifiers, with VRAM scaling predictably as the length of the historical data sequence increases.
format Preprint
id arxiv_https___arxiv_org_abs_2604_07027
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Learning to Query History: Nonstationary Classification via Learned Retrieval
Gammell, Jimmy
Thapaliya, Bishal
Jung, Yoon
Ohib, Riyasat
Fehri, Bilel
Chakrabarti, Deepayan
Machine Learning
Nonstationarity is ubiquitous in practical classification settings, leading deployed models to perform poorly even when they generalize well to holdout sets available at training time. We address this by reframing nonstationary classification as time series prediction: rather than predicting from the current input alone, we condition the classifier on a sequence of historical labeled examples that extends beyond the training cutoff. To scale to large sequences, we introduce a learned discrete retrieval mechanism that samples relevant historical examples via input-dependent queries, trained end-to-end with the classifier using a score-based gradient estimator. This enables the full corpus of historical data to remain on an arbitrary filesystem during training and deployment. Experiments on synthetic benchmarks and Amazon Reviews '23 (electronics category) show improved robustness to distribution shift compared to standard classifiers, with VRAM scaling predictably as the length of the historical data sequence increases.
title Learning to Query History: Nonstationary Classification via Learned Retrieval
topic Machine Learning
url https://arxiv.org/abs/2604.07027