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Percentile speculative execution¶
This policy has access to Metrics shared with session, and triggers
speculative execution when the request to the current host is above a
given percentile.
This policy requires enabling crate feature "metrics" to be available.
Example¶
To use this policy in Session:
use std::{sync::Arc, time::Duration};
use scylla::client::session::Session;
use scylla::client::session_builder::SessionBuilder;
use scylla::{
policies::speculative_execution::PercentileSpeculativeExecutionPolicy,
client::execution_profile::ExecutionProfile,
};
let policy = PercentileSpeculativeExecutionPolicy {
max_retry_count: 3,
percentile: 99.0,
};
let handle = ExecutionProfile::builder()
.speculative_execution_policy(Some(Arc::new(policy)))
.build()
.into_handle();
let session: Session = SessionBuilder::new()
.known_node("127.0.0.1:9042")
.default_execution_profile_handle(handle)
.build()
.await?;