Struct BatchReadOnlyTransaction 

pub struct BatchReadOnlyTransaction { /* private fields */ }

A read-only transaction that can be used to partition reads and queries and execute these in parallel across multiple workers.

Example

let db_client = spanner.database_client("projects/p/instances/i/databases/d").build().await?;
let transaction = db_client.batch_read_only_transaction().build().await?;
let stmt = Statement::builder("SELECT * FROM users WHERE id = @id")
    .add_param("id", &42)
    .build();
let options = PartitionOptions::default()
    .set_max_partitions(10);
let partitions = transaction.partition_query(stmt, options).await?;

// partitions can be sent to other workers for parallel execution

Implementations

impl BatchReadOnlyTransaction

pub fn read_timestamp(&self) -> Option<Timestamp>

Returns the read timestamp chosen for the transaction.

pub async fn partition_query<T: Into<Statement>>( &self, statement: T, options: PartitionOptions, ) -> Result<Vec<Partition>>

Creates a set of partitions that can be used to execute a query in parallel.

Example

let db = spanner.database_client("projects/p/instances/i/databases/d").build().await?;
let transaction = db.batch_read_only_transaction().build().await?;

let stmt = Statement::builder("SELECT * FROM users WHERE id = @id")
    .add_param("id", &42)
    .build();
let options = PartitionOptions::default()
    .set_max_partitions(10);
let partitions = transaction.partition_query(stmt, options).await?;

pub async fn partition_read<T: Into<ReadRequest>>( &self, read: T, options: PartitionOptions, ) -> Result<Vec<Partition>>

Creates a set of partitions that can be used to execute a read in parallel.

Example

let db = spanner.database_client("projects/p/instances/i/databases/d").build().await?;
let transaction = db.batch_read_only_transaction().build().await?;

let read = ReadRequest::builder("users", vec!["id".to_string(), "name".to_string()])
    .with_keys(KeySet::all())
    .build();
let options = PartitionOptions::default()
    .set_max_partitions(10);
let partitions = transaction.partition_read(read, options).await?;

Trait Implementations

impl Debug for BatchReadOnlyTransaction

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.