Timestamp generators | ScyllaDB Docs

Timestamp generators¶

If you want to generate timestamps on the client side you can provide a TimestampGenerator to a SessionBuilder when creating a Session. Then every executed statement will have attached a new timestamp generated by the provided TimestampGenerator. Timestamps are set according to precendence:

USING TIMESTAMP in the query itself

Manually using set_timestamp on the query

Timestamp generated by the generator

Simple Timestamp Generator¶

Most basic client-side timestamp generator. Generates timestamp based on system clock. Provides no guarantees and panics when the system clock provides timestamp before the unix epoch.

Monotonic Timestamp Generator¶

Client-side timestamp generator. Guarantees monotonic timestamps based on the system clock, with automatic timestamp incrementation if the system clock timestamp would not be monotonic. If the clock skew exceeds warning_threshold of the generator (can be changed with with_warning_times, 1s by default) user will be warned with timestamp generation with warning_interval cooldown period (can be changed with with_warning_times, 1s by default) to not spam the user. If user does not want to be warned about the clock skew, the warnings can be turned off with without_warnings function.

# extern crate scylla;
# use std::error::Error;
# async fn check_only_compiles() -> Result<(), Box<dyn std::error::Error>> {
use scylla::client::session::Session;
use scylla::client::session_builder::SessionBuilder;
use scylla::policies::timestamp_generator::MonotonicTimestampGenerator;
use scylla::query::Query;
use std::sync::Arc;

let session: Session = SessionBuilder::new()
    .known_node("127.0.0.1:9042")
    .timestamp_generator(Arc::new(MonotonicTimestampGenerator::new()))
    .build()
    .await?;

// This query will have a timestamp generated 
// by the monotonic timestamp generator
let my_query: Query = Query::new("INSERT INTO ks.tab (a) VALUES(?)");
let to_insert: i32 = 12345;
session.query_unpaged(my_query, (to_insert,)).await?;
# Ok(())
# }

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