Struct QueryOptions 

#[non_exhaustive]
pub struct QueryOptions {
    pub optimizer_version: String,
    pub optimizer_statistics_package: String,
    /* private fields */
}

Query optimizer configuration.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

optimizer_version: String

An option to control the selection of optimizer version.

This parameter allows individual queries to pick different query optimizer versions.

Specifying latest as a value instructs Cloud Spanner to use the latest supported query optimizer version. If not specified, Cloud Spanner uses the optimizer version set at the database level options. Any other positive integer (from the list of supported optimizer versions) overrides the default optimizer version for query execution.

The list of supported optimizer versions can be queried from SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS.

Executing a SQL statement with an invalid optimizer version fails with an INVALID_ARGUMENT error.

See https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer for more information on managing the query optimizer.

The optimizer_version statement hint has precedence over this setting.

optimizer_statistics_package: String

An option to control the selection of optimizer statistics package.

This parameter allows individual queries to use a different query optimizer statistics package.

Specifying latest as a value instructs Cloud Spanner to use the latest generated statistics package. If not specified, Cloud Spanner uses the statistics package set at the database level options, or the latest package if the database option isn’t set.

The statistics package requested by the query has to be exempt from garbage collection. This can be achieved with the following DDL statement:

ALTER STATISTICS <package_name> SET OPTIONS (allow_gc=false)

The list of available statistics packages can be queried from INFORMATION_SCHEMA.SPANNER_STATISTICS.

Executing a SQL statement with an invalid optimizer statistics package or with a statistics package that allows garbage collection fails with an INVALID_ARGUMENT error.

Implementations

impl QueryOptions

pub fn new() -> Self

Creates a new default instance.

pub fn set_optimizer_version<T: Into<String>>(self, v: T) -> Self

Sets the value of optimizer_version.

pub fn set_optimizer_statistics_package<T: Into<String>>(self, v: T) -> Self

Sets the value of optimizer_statistics_package.

Trait Implementations

impl Clone for QueryOptions

fn clone(&self) -> QueryOptions

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for QueryOptions

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

Formats the value using the given formatter.

impl Default for QueryOptions

fn default() -> QueryOptions

Returns the “default value” for a type.

impl Message for QueryOptions

fn typename() -> &'static str

The typename of this message.

impl PartialEq for QueryOptions

fn eq(&self, other: &QueryOptions) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for QueryOptions