Method sequence_set_variable

src/adapter/src/coord/sequencer/inner.rs:1892–1983

(
        &self,
        session: &mut Session,
        plan: plan::SetVariablePlan,
    )

    #[instrument]
    pub(super) fn sequence_set_variable(
        &self,
        session: &mut Session,
        plan: plan::SetVariablePlan,
    ) -> Result<ExecuteResponse, AdapterError> {
        let (name, local) = (plan.name, plan.local);
        if &name == TRANSACTION_ISOLATION_VAR_NAME {
            self.validate_set_isolation_level(session)?;
        }
        if &name == vars::CLUSTER.name() {
            self.validate_set_cluster(session)?;
        }

        let vars = session.vars_mut();
        let values = match plan.value {
            plan::VariableValue::Default => None,
            plan::VariableValue::Values(values) => Some(values),
        };

        match values {
            Some(values) => {
                vars.set(
                    self.catalog().system_config(),
                    &name,
                    VarInput::SqlSet(&values),
                    local,
                )?;

                let vars = session.vars();

                // Emit a warning when deprecated variables are used.
                // TODO(database-issues#8069) remove this after sufficient time has passed
                if name == vars::OLD_AUTO_ROUTE_CATALOG_QUERIES {
                    session.add_notice(AdapterNotice::AutoRouteIntrospectionQueriesUsage);
                } else if name == vars::CLUSTER.name()
                    && values[0] == vars::OLD_CATALOG_SERVER_CLUSTER
                {
                    session.add_notice(AdapterNotice::IntrospectionClusterUsage);
                }

                // Database or cluster value does not correspond to a catalog item.
                if name.as_str() == vars::DATABASE.name()
                    && matches!(
                        self.catalog().resolve_database(vars.database()),
                        Err(CatalogError::UnknownDatabase(_))
                    )
                    && session.vars().current_object_missing_warnings()
                {
                    let name = vars.database().to_string();
                    session.add_notice(AdapterNotice::DatabaseDoesNotExist { name });
                } else if name.as_str() == vars::CLUSTER.name()
                    && matches!(
                        self.catalog().resolve_cluster(vars.cluster()),
                        Err(CatalogError::UnknownCluster(_))
                    )
                    && session.vars().current_object_missing_warnings()
                {
                    let name = vars.cluster().to_string();