Enum FrontendClient 

pub enum FrontendClient {
    Distributed {
        meta_client: Arc<MetaClient>,
        chnl_mgr: ChannelManager,
        query: QueryOptions,
        batch_opts: BatchingModeOptions,
    },
    Standalone {
        database_client: HandlerMutable,
        query: QueryOptions,
    },
}

A simple frontend client able to execute sql using grpc protocol

This is for computation-heavy query which need to offload computation to frontend, lifting the load from flownode

Variants

Distributed

Fields

meta_client: Arc<MetaClient>

chnl_mgr: ChannelManager

query: QueryOptions

batch_opts: BatchingModeOptions

Standalone

Fields

database_client: HandlerMutable

for the sake of simplicity still use grpc even in standalone mode notice the client here should all be lazy, so that can wait after frontend is booted then make conn

query: QueryOptions

Implementations

impl FrontendClient

pub fn from_empty_grpc_handler(query: QueryOptions) -> (Self, HandlerMutable)

Create a new empty frontend client, with a HandlerMutable to set the grpc handler later

pub async fn wait_initialized(&self)

Waits until the frontend client is initialized.

pub fn from_meta_client( meta_client: Arc<MetaClient>, query: QueryOptions, batch_opts: BatchingModeOptions, ) -> Result<Self, Error>

pub fn from_grpc_handler( grpc_handler: Weak<dyn GrpcQueryHandlerWithBoxedError>, query: QueryOptions, ) -> Self

impl FrontendClient

pub(crate) async fn scan_for_frontend(&self) -> Result<Vec<Peer>, Error>

scan for available frontend from metadata

pub(crate) async fn check_all_frontends_without_auth( &self, frontends: &[Peer], ) -> Result<Vec<String>, Error>

Probes all discovered frontends without auth.

Returns non-auth failures to allow callers to retry transient connectivity errors. Authentication failures are returned immediately because they mean a frontend advertised an auth-protected endpoint to flownodes.

async fn get_random_active_frontend( &self, catalog: &str, schema: &str, ) -> Result<DatabaseWithPeer, Error>

Get a frontend discovered by metasrv and verified with a query probe.

pub async fn create( &self, create: CreateTableExpr, catalog: &str, schema: &str, ) -> Result<u32, Error>

pub async fn sql( &self, catalog: &str, schema: &str, sql: &str, ) -> Result<Output, Error>

Execute a SQL statement on the frontend.

pub(crate) async fn query_with_terminal_metrics( &self, catalog: &str, schema: &str, request: QueryRequest, extensions: &[(&str, &str)], snapshot_seqs: &HashMap<u64, u64>, peer_desc: &mut Option<PeerDesc>, ) -> Result<OutputWithMetrics, Error>

Execute a flow query and return terminal metrics. snapshot_seqs are optional read upper bounds used only by snapshot-fenced repair chunks.

pub(crate) async fn handle( &self, req: Request, catalog: &str, schema: &str, peer_desc: &mut Option<PeerDesc>, ) -> Result<u32, Error>

Handle a request to frontend

Trait Implementations

impl Clone for FrontendClient

fn clone(&self) -> FrontendClient

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FrontendClient

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

Formats the value using the given formatter.