optuna.storages.RetryFailedTrialCallback

class optuna.storages.RetryFailedTrialCallback(max_retry=None)[source]

Retry a failed trial up to a maximum number of times.

When a trial fails, this callback can be used with the optuna.storage class to recreate the trial in TrialState.WAITING to queue up the trial to be run again.

This is helpful in environments where trials may fail due to external conditions, such as being preempted by other processes.

Usage:

import optuna
from optuna.storages import RetryFailedTrialCallback

storage = optuna.storages.RDBStorage(
    url="sqlite:///:memory:",
    heartbeat_interval=60,
    grace_period=120,
    failed_trial_callback=RetryFailedTrialCallback(max_retry=3),
)

study = optuna.create_study(
    storage=storage,
)
Parameters

max_retry – The max number of times a trial can be retried. Must be set to None or an integer. If set to the default value of None will retry indefinitely. If set to an integer, will only retry that many times.

Note

Added in v2.8.0 as an experimental feature. The interface may change in newer versions without prior notice. See https://github.com/optuna/optuna/releases/tag/v2.8.0.

Methods

retried_trial_number(trial)

Return the number of the trial being retried.

static retried_trial_number(trial)[source]

Return the number of the trial being retried.

Parameters

trial (optuna.trial._frozen.FrozenTrial) – The trial object.

Returns

The number of the previous trial. If not retry of a previous trial, returns None.

Return type

Optional[int]

Note

Added in v2.8.0 as an experimental feature. The interface may change in newer versions without prior notice. See https://github.com/optuna/optuna/releases/tag/v2.8.0.