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Use cached study direction and trial for _CachedStorage's get_best_trial#6270

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y0z merged 1 commit intooptuna:masterfrom
not522:get-best-trial-cache
Sep 29, 2025
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Use cached study direction and trial for _CachedStorage's get_best_trial#6270
y0z merged 1 commit intooptuna:masterfrom
not522:get-best-trial-cache

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@not522 not522 commented Sep 10, 2025 •
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Motivation

Currently, _CachedStorage's get_best_trial just calls the method of the backend storage (RDBStorage). However, performance can be improved by using cached study directions and trials.

Description of the changes

  • Introduce _get_best_trial_id in RDBStorage
  • Use cached study direction and trial for _CachedStorage's get_best_trial

Benchmark

import optuna

def objective(trial: optuna.Trial) -> float:
    x = trial.suggest_float("x", -100, 100)
    y = trial.suggest_int("y", -100, 100)
    return x**2 + y**2

sampler = optuna.samplers.TPESampler(seed=42, multivariate=True, constant_liar=True)
study = optuna.create_study(sampler=sampler, storage="sqlite:///tmp.db")
study.optimize(objective, n_trials=1000)
master PR
12.255s 11.368s

@not522 not522 added the enhancement Change that does not break compatibility and not affect public interfaces, but improves performance. label Sep 10, 2025
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y0z commented Sep 11, 2025

@sawa3030 Could you review this PR?

@y0z y0z assigned sawa3030 and y0z Sep 11, 2025
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github-actions bot commented Sep 18, 2025

This pull request has not seen any recent activity.

@github-actions github-actions bot added the stale Exempt from stale bot labeling. label Sep 18, 2025
sawa3030
sawa3030 reviewed Sep 19, 2025
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optuna/storages/_cached_storage.py
)
direction = _directions[0]
trial_id = self._backend._get_best_trial_id(study_id, direction)
return self.get_trial(trial_id)
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@sawa3030 sawa3030 Sep 19, 2025

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I'm sorry for keeping you waiting. I have one question: I’m not entirely sure how the trials in the cached storage are updated. I tested locally and confirmed that this PR works as expected, but I’m still unclear why this line works without explicitly calling self._backend.get_trial(trial_id).

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@not522 not522 Sep 19, 2025

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_CachedStorage's get_trial method returns the cached trial data if available, or accesses the remote database if not. This helps reduce unnecessary database access.

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@sawa3030 sawa3030 Sep 19, 2025

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Thank you very much. I have overlooked that point.

sawa3030
sawa3030 approved these changes Sep 19, 2025
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LGTM

@github-actions github-actions bot removed the stale Exempt from stale bot labeling. label Sep 21, 2025
y0z
y0z approved these changes Sep 29, 2025
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LGTM. In my environment, the speedup was very small, but the code changes are fine and can be merged.

@y0z y0z merged commit 75114c0 into optuna:master Sep 29, 2025
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@y0z y0z added this to the v4.6.0 milestone Sep 29, 2025
@not522 not522 deleted the get-best-trial-cache branch September 29, 2025 09:40
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@y0z y0z y0z approved these changes

@sawa3030 sawa3030 sawa3030 approved these changes

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@y0z y0z

@sawa3030 sawa3030

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enhancement Change that does not break compatibility and not affect public interfaces, but improves performance.

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v4.6.0

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@not522 @y0z @sawa3030