leekeiabstraction commented on code in PR #216: URL: https://github.com/apache/fluss-rust/pull/216#discussion_r2745624585
########## crates/fluss/src/client/lookup/lookup_sender.rs: ########## @@ -0,0 +1,444 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Lookup sender that processes batched lookup requests. +//! +//! The sender runs as a background task, draining lookups from the queue, +//! grouping them by destination server, and sending batched requests. + +use super::{LookupQuery, LookupQueue}; +use crate::client::metadata::Metadata; +use crate::error::{Error, FlussError, Result}; +use crate::metadata::TableBucket; +use crate::proto::LookupResponse; +use crate::rpc::message::LookupRequest; +use log::{debug, error, warn}; +use std::collections::HashMap; +use std::sync::Arc; +use std::sync::atomic::{AtomicBool, Ordering}; +use std::time::Duration; +use tokio::sync::{Semaphore, mpsc}; + +/// Lookup sender that batches and sends lookup requests. +pub struct LookupSender { + /// Metadata for leader lookup + metadata: Arc<Metadata>, + /// The lookup queue to drain from + queue: LookupQueue, + /// Channel to re-enqueue failed lookups + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + /// Semaphore to limit in-flight requests + inflight_semaphore: Arc<Semaphore>, + /// Maximum number of retries + max_retries: i32, + /// Whether the sender is running + running: AtomicBool, + /// Whether to force close (abandon pending lookups) + force_close: AtomicBool, +} + +/// A batch of lookups going to the same table bucket. +struct LookupBatch { + table_bucket: TableBucket, + lookups: Vec<LookupQuery>, + keys: Vec<Vec<u8>>, +} + +impl LookupBatch { + fn new(table_bucket: TableBucket) -> Self { + Self { + table_bucket, + lookups: Vec::new(), + keys: Vec::new(), + } + } + + fn add_lookup(&mut self, lookup: LookupQuery) { + self.keys.push(lookup.key().to_vec()); + self.lookups.push(lookup); + } + + fn complete(&mut self, values: Vec<Option<Vec<u8>>>) { + if values.len() != self.lookups.len() { + let err_msg = format!( + "The number of return values ({}) does not match the number of lookups ({})", + values.len(), + self.lookups.len() + ); + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: err_msg.clone(), + source: None, + })); + } + return; + } + + for (lookup, value) in self.lookups.iter_mut().zip(values.into_iter()) { + lookup.complete(Ok(value)); + } + } + + fn complete_exceptionally(&mut self, error_msg: &str) { + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: error_msg.to_string(), + source: None, + })); + } + } +} + +impl LookupSender { + /// Creates a new lookup sender. + pub fn new( + metadata: Arc<Metadata>, + queue: LookupQueue, + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + max_inflight_requests: usize, + max_retries: i32, + ) -> Self { + Self { + metadata, + queue, + re_enqueue_tx, + inflight_semaphore: Arc::new(Semaphore::new(max_inflight_requests)), + max_retries, + running: AtomicBool::new(true), + force_close: AtomicBool::new(false), + } + } + + /// Runs the sender loop. + pub async fn run(&mut self) { + debug!("Starting Fluss lookup sender"); + + while self.running.load(Ordering::Acquire) { + if let Err(e) = self.run_once(false).await { + error!("Error in lookup sender: {}", e); + } + } + + debug!("Beginning shutdown of lookup sender, sending remaining lookups"); + + // Process remaining lookups during shutdown + if !self.force_close.load(Ordering::Acquire) && self.queue.has_undrained() { + if let Err(e) = self.run_once(true).await { + error!("Error during lookup sender shutdown: {}", e); + } + } + Review Comment: Should we also port over the TODO comments from Java side? ########## crates/fluss/src/client/lookup/lookup_sender.rs: ########## @@ -0,0 +1,444 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Lookup sender that processes batched lookup requests. +//! +//! The sender runs as a background task, draining lookups from the queue, +//! grouping them by destination server, and sending batched requests. + +use super::{LookupQuery, LookupQueue}; +use crate::client::metadata::Metadata; +use crate::error::{Error, FlussError, Result}; +use crate::metadata::TableBucket; +use crate::proto::LookupResponse; +use crate::rpc::message::LookupRequest; +use log::{debug, error, warn}; +use std::collections::HashMap; +use std::sync::Arc; +use std::sync::atomic::{AtomicBool, Ordering}; +use std::time::Duration; +use tokio::sync::{Semaphore, mpsc}; + +/// Lookup sender that batches and sends lookup requests. +pub struct LookupSender { + /// Metadata for leader lookup + metadata: Arc<Metadata>, + /// The lookup queue to drain from + queue: LookupQueue, + /// Channel to re-enqueue failed lookups + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + /// Semaphore to limit in-flight requests + inflight_semaphore: Arc<Semaphore>, + /// Maximum number of retries + max_retries: i32, + /// Whether the sender is running + running: AtomicBool, + /// Whether to force close (abandon pending lookups) + force_close: AtomicBool, +} + +/// A batch of lookups going to the same table bucket. +struct LookupBatch { + table_bucket: TableBucket, + lookups: Vec<LookupQuery>, + keys: Vec<Vec<u8>>, +} + +impl LookupBatch { + fn new(table_bucket: TableBucket) -> Self { + Self { + table_bucket, + lookups: Vec::new(), + keys: Vec::new(), + } + } + + fn add_lookup(&mut self, lookup: LookupQuery) { + self.keys.push(lookup.key().to_vec()); + self.lookups.push(lookup); + } + + fn complete(&mut self, values: Vec<Option<Vec<u8>>>) { + if values.len() != self.lookups.len() { + let err_msg = format!( + "The number of return values ({}) does not match the number of lookups ({})", + values.len(), + self.lookups.len() + ); + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: err_msg.clone(), + source: None, + })); + } + return; + } + + for (lookup, value) in self.lookups.iter_mut().zip(values.into_iter()) { + lookup.complete(Ok(value)); + } + } + + fn complete_exceptionally(&mut self, error_msg: &str) { + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: error_msg.to_string(), + source: None, + })); + } + } +} + +impl LookupSender { + /// Creates a new lookup sender. + pub fn new( + metadata: Arc<Metadata>, + queue: LookupQueue, + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + max_inflight_requests: usize, + max_retries: i32, + ) -> Self { + Self { + metadata, + queue, + re_enqueue_tx, + inflight_semaphore: Arc::new(Semaphore::new(max_inflight_requests)), + max_retries, + running: AtomicBool::new(true), + force_close: AtomicBool::new(false), + } + } + + /// Runs the sender loop. + pub async fn run(&mut self) { + debug!("Starting Fluss lookup sender"); + + while self.running.load(Ordering::Acquire) { + if let Err(e) = self.run_once(false).await { + error!("Error in lookup sender: {}", e); + } + } + + debug!("Beginning shutdown of lookup sender, sending remaining lookups"); + + // Process remaining lookups during shutdown + if !self.force_close.load(Ordering::Acquire) && self.queue.has_undrained() { + if let Err(e) = self.run_once(true).await { + error!("Error during lookup sender shutdown: {}", e); + } + } + + debug!("Lookup sender shutdown complete"); + } + + /// Runs a single iteration of the sender loop. + async fn run_once(&mut self, drain_all: bool) -> Result<()> { + let lookups = if drain_all { + self.queue.drain_all() + } else { + self.queue.drain().await + }; + + self.send_lookups(lookups).await + } + + /// Groups and sends lookups to appropriate servers. + async fn send_lookups(&self, lookups: Vec<LookupQuery>) -> Result<()> { Review Comment: Is an Err ever returned from within this method? ########## crates/fluss/src/client/lookup/lookup_sender.rs: ########## @@ -0,0 +1,444 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Lookup sender that processes batched lookup requests. +//! +//! The sender runs as a background task, draining lookups from the queue, +//! grouping them by destination server, and sending batched requests. + +use super::{LookupQuery, LookupQueue}; +use crate::client::metadata::Metadata; +use crate::error::{Error, FlussError, Result}; +use crate::metadata::TableBucket; +use crate::proto::LookupResponse; +use crate::rpc::message::LookupRequest; +use log::{debug, error, warn}; +use std::collections::HashMap; +use std::sync::Arc; +use std::sync::atomic::{AtomicBool, Ordering}; +use std::time::Duration; +use tokio::sync::{Semaphore, mpsc}; + +/// Lookup sender that batches and sends lookup requests. +pub struct LookupSender { + /// Metadata for leader lookup + metadata: Arc<Metadata>, + /// The lookup queue to drain from + queue: LookupQueue, + /// Channel to re-enqueue failed lookups + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + /// Semaphore to limit in-flight requests + inflight_semaphore: Arc<Semaphore>, + /// Maximum number of retries + max_retries: i32, + /// Whether the sender is running + running: AtomicBool, + /// Whether to force close (abandon pending lookups) + force_close: AtomicBool, +} + +/// A batch of lookups going to the same table bucket. +struct LookupBatch { + table_bucket: TableBucket, + lookups: Vec<LookupQuery>, + keys: Vec<Vec<u8>>, +} + +impl LookupBatch { + fn new(table_bucket: TableBucket) -> Self { + Self { + table_bucket, + lookups: Vec::new(), + keys: Vec::new(), + } + } + + fn add_lookup(&mut self, lookup: LookupQuery) { + self.keys.push(lookup.key().to_vec()); + self.lookups.push(lookup); + } + + fn complete(&mut self, values: Vec<Option<Vec<u8>>>) { + if values.len() != self.lookups.len() { + let err_msg = format!( + "The number of return values ({}) does not match the number of lookups ({})", + values.len(), + self.lookups.len() + ); + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: err_msg.clone(), + source: None, + })); + } + return; + } + + for (lookup, value) in self.lookups.iter_mut().zip(values.into_iter()) { + lookup.complete(Ok(value)); + } + } + + fn complete_exceptionally(&mut self, error_msg: &str) { + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: error_msg.to_string(), + source: None, + })); + } + } +} + +impl LookupSender { + /// Creates a new lookup sender. + pub fn new( + metadata: Arc<Metadata>, + queue: LookupQueue, + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + max_inflight_requests: usize, + max_retries: i32, + ) -> Self { + Self { + metadata, + queue, + re_enqueue_tx, + inflight_semaphore: Arc::new(Semaphore::new(max_inflight_requests)), + max_retries, + running: AtomicBool::new(true), + force_close: AtomicBool::new(false), + } + } + + /// Runs the sender loop. + pub async fn run(&mut self) { + debug!("Starting Fluss lookup sender"); + + while self.running.load(Ordering::Acquire) { + if let Err(e) = self.run_once(false).await { + error!("Error in lookup sender: {}", e); + } + } + + debug!("Beginning shutdown of lookup sender, sending remaining lookups"); + + // Process remaining lookups during shutdown + if !self.force_close.load(Ordering::Acquire) && self.queue.has_undrained() { + if let Err(e) = self.run_once(true).await { + error!("Error during lookup sender shutdown: {}", e); + } + } + + debug!("Lookup sender shutdown complete"); + } + + /// Runs a single iteration of the sender loop. + async fn run_once(&mut self, drain_all: bool) -> Result<()> { + let lookups = if drain_all { + self.queue.drain_all() + } else { + self.queue.drain().await + }; + + self.send_lookups(lookups).await + } + + /// Groups and sends lookups to appropriate servers. + async fn send_lookups(&self, lookups: Vec<LookupQuery>) -> Result<()> { + if lookups.is_empty() { + return Ok(()); + } + + // Group by leader + let lookup_batches = self.group_by_leader(lookups); + + if lookup_batches.is_empty() && !self.queue.has_undrained() { + // No lookups to send and queue is empty, sleep to avoid busy loop + tokio::time::sleep(Duration::from_millis(100)).await; + return Ok(()); + } + + // Send batches to each destination + for (destination, batches) in lookup_batches { + self.send_lookup_request(destination, batches).await; + } + + Ok(()) + } + + /// Groups lookups by leader server. + fn group_by_leader( + &self, + lookups: Vec<LookupQuery>, + ) -> HashMap<i32, HashMap<TableBucket, LookupBatch>> { + let cluster = self.metadata.get_cluster(); + let mut batches_by_leader: HashMap<i32, HashMap<TableBucket, LookupBatch>> = HashMap::new(); + + for lookup in lookups { + let table_bucket = lookup.table_bucket().clone(); + + // Find leader for this bucket + let leader = match cluster.leader_for(&table_bucket) { + Some(leader) => leader.id(), + None => { + warn!( + "No leader found for table bucket {} during lookup", + table_bucket + ); + self.re_enqueue_lookup(lookup); + continue; + } + }; + + batches_by_leader + .entry(leader) + .or_default() + .entry(table_bucket.clone()) + .or_insert_with(|| LookupBatch::new(table_bucket)) + .add_lookup(lookup); + } + + batches_by_leader + } + + /// Sends lookup requests to a specific destination server. + async fn send_lookup_request( + &self, + destination: i32, + batches_by_bucket: HashMap<TableBucket, LookupBatch>, + ) { + // Group by table_id for request batching + let mut batches_by_table: HashMap<i64, Vec<LookupBatch>> = HashMap::new(); Review Comment: Nit: Use TableId type. ########## crates/fluss/src/client/lookup/lookup_queue.rs: ########## @@ -0,0 +1,130 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Lookup queue for buffering pending lookup operations. +//! +//! This queue buffers lookup operations and provides batched draining +//! to improve throughput by reducing network round trips. + +use super::LookupQuery; +use std::time::Duration; +use tokio::sync::mpsc; +use tokio::time::timeout; + +/// A queue that buffers pending lookup operations and provides batched draining. +/// +/// The queue supports two types of entries: +/// - New lookups from client calls +/// - Re-enqueued lookups from retry logic +/// +/// Re-enqueued lookups are prioritized over new lookups to ensure fair processing. +pub struct LookupQueue { + /// Channel for receiving lookup requests + lookup_rx: mpsc::Receiver<LookupQuery>, + /// Channel for receiving re-enqueued lookups + re_enqueue_rx: mpsc::UnboundedReceiver<LookupQuery>, + /// Maximum batch size for draining + max_batch_size: usize, + /// Timeout for batch collection + batch_timeout: Duration, +} + +impl LookupQueue { + /// Creates a new lookup queue with the specified configuration. + pub fn new( + queue_size: usize, + max_batch_size: usize, + batch_timeout_ms: u64, + ) -> ( + Self, + mpsc::Sender<LookupQuery>, + mpsc::UnboundedSender<LookupQuery>, + ) { + let (lookup_tx, lookup_rx) = mpsc::channel(queue_size); + let (re_enqueue_tx, re_enqueue_rx) = mpsc::unbounded_channel(); + + let queue = Self { + lookup_rx, + re_enqueue_rx, + max_batch_size, + batch_timeout: Duration::from_millis(batch_timeout_ms), + }; + + (queue, lookup_tx, re_enqueue_tx) + } + + /// Drains a batch of lookup queries from the queue. + pub async fn drain(&mut self) -> Vec<LookupQuery> { Review Comment: This implementation seems to subtly differ from java: Java side: Loop repeatedly through re-enqueud and queued until batch size is reached or deadline reached. Rust side: Loop once through re-enqueued and then repeatedly through queued until batch size or deadline reached. The java side always prioritise re-enqueued. Is my understanding correct and if so what's the motivation of the subtle difference? I think Java side is safer as it will always drain the re-enqueued which is unbounded and let queue back pressure take effect. ########## crates/fluss/src/client/lookup/lookup_sender.rs: ########## @@ -0,0 +1,444 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Lookup sender that processes batched lookup requests. +//! +//! The sender runs as a background task, draining lookups from the queue, +//! grouping them by destination server, and sending batched requests. + +use super::{LookupQuery, LookupQueue}; +use crate::client::metadata::Metadata; +use crate::error::{Error, FlussError, Result}; +use crate::metadata::TableBucket; +use crate::proto::LookupResponse; +use crate::rpc::message::LookupRequest; +use log::{debug, error, warn}; +use std::collections::HashMap; +use std::sync::Arc; +use std::sync::atomic::{AtomicBool, Ordering}; +use std::time::Duration; +use tokio::sync::{Semaphore, mpsc}; + +/// Lookup sender that batches and sends lookup requests. +pub struct LookupSender { + /// Metadata for leader lookup + metadata: Arc<Metadata>, + /// The lookup queue to drain from + queue: LookupQueue, + /// Channel to re-enqueue failed lookups + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + /// Semaphore to limit in-flight requests + inflight_semaphore: Arc<Semaphore>, + /// Maximum number of retries + max_retries: i32, + /// Whether the sender is running + running: AtomicBool, + /// Whether to force close (abandon pending lookups) + force_close: AtomicBool, +} + +/// A batch of lookups going to the same table bucket. +struct LookupBatch { + table_bucket: TableBucket, + lookups: Vec<LookupQuery>, + keys: Vec<Vec<u8>>, +} + +impl LookupBatch { + fn new(table_bucket: TableBucket) -> Self { + Self { + table_bucket, + lookups: Vec::new(), + keys: Vec::new(), + } + } + + fn add_lookup(&mut self, lookup: LookupQuery) { + self.keys.push(lookup.key().to_vec()); + self.lookups.push(lookup); + } + + fn complete(&mut self, values: Vec<Option<Vec<u8>>>) { + if values.len() != self.lookups.len() { + let err_msg = format!( + "The number of return values ({}) does not match the number of lookups ({})", + values.len(), + self.lookups.len() + ); + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: err_msg.clone(), + source: None, + })); + } + return; + } + + for (lookup, value) in self.lookups.iter_mut().zip(values.into_iter()) { + lookup.complete(Ok(value)); + } + } + + fn complete_exceptionally(&mut self, error_msg: &str) { + for lookup in &mut self.lookups { + lookup.complete(Err(Error::UnexpectedError { + message: error_msg.to_string(), + source: None, + })); + } + } +} + +impl LookupSender { + /// Creates a new lookup sender. + pub fn new( + metadata: Arc<Metadata>, + queue: LookupQueue, + re_enqueue_tx: mpsc::UnboundedSender<LookupQuery>, + max_inflight_requests: usize, + max_retries: i32, + ) -> Self { + Self { + metadata, + queue, + re_enqueue_tx, + inflight_semaphore: Arc::new(Semaphore::new(max_inflight_requests)), + max_retries, + running: AtomicBool::new(true), + force_close: AtomicBool::new(false), + } + } + + /// Runs the sender loop. + pub async fn run(&mut self) { + debug!("Starting Fluss lookup sender"); + + while self.running.load(Ordering::Acquire) { + if let Err(e) = self.run_once(false).await { + error!("Error in lookup sender: {}", e); + } + } + + debug!("Beginning shutdown of lookup sender, sending remaining lookups"); + + // Process remaining lookups during shutdown + if !self.force_close.load(Ordering::Acquire) && self.queue.has_undrained() { + if let Err(e) = self.run_once(true).await { + error!("Error during lookup sender shutdown: {}", e); + } + } + + debug!("Lookup sender shutdown complete"); + } + + /// Runs a single iteration of the sender loop. + async fn run_once(&mut self, drain_all: bool) -> Result<()> { + let lookups = if drain_all { + self.queue.drain_all() + } else { + self.queue.drain().await + }; + + self.send_lookups(lookups).await + } + + /// Groups and sends lookups to appropriate servers. + async fn send_lookups(&self, lookups: Vec<LookupQuery>) -> Result<()> { + if lookups.is_empty() { + return Ok(()); + } + + // Group by leader + let lookup_batches = self.group_by_leader(lookups); + + if lookup_batches.is_empty() && !self.queue.has_undrained() { + // No lookups to send and queue is empty, sleep to avoid busy loop + tokio::time::sleep(Duration::from_millis(100)).await; + return Ok(()); + } + + // Send batches to each destination + for (destination, batches) in lookup_batches { + self.send_lookup_request(destination, batches).await; + } + + Ok(()) + } + + /// Groups lookups by leader server. + fn group_by_leader( + &self, + lookups: Vec<LookupQuery>, + ) -> HashMap<i32, HashMap<TableBucket, LookupBatch>> { + let cluster = self.metadata.get_cluster(); + let mut batches_by_leader: HashMap<i32, HashMap<TableBucket, LookupBatch>> = HashMap::new(); + + for lookup in lookups { + let table_bucket = lookup.table_bucket().clone(); + + // Find leader for this bucket + let leader = match cluster.leader_for(&table_bucket) { + Some(leader) => leader.id(), + None => { + warn!( + "No leader found for table bucket {} during lookup", + table_bucket + ); + self.re_enqueue_lookup(lookup); + continue; + } + }; + + batches_by_leader + .entry(leader) + .or_default() + .entry(table_bucket.clone()) + .or_insert_with(|| LookupBatch::new(table_bucket)) + .add_lookup(lookup); + } + + batches_by_leader + } + + /// Sends lookup requests to a specific destination server. + async fn send_lookup_request( + &self, + destination: i32, + batches_by_bucket: HashMap<TableBucket, LookupBatch>, + ) { + // Group by table_id for request batching + let mut batches_by_table: HashMap<i64, Vec<LookupBatch>> = HashMap::new(); + for (table_bucket, batch) in batches_by_bucket { + batches_by_table + .entry(table_bucket.table_id()) + .or_default() + .push(batch); + } + + let cluster = self.metadata.get_cluster(); + let tablet_server = match cluster.get_tablet_server(destination) { + Some(server) => server.clone(), + None => { + let err_msg = format!("Server {} is not found in metadata cache", destination); + for batches in batches_by_table.into_values() { + for mut batch in batches { + self.handle_lookup_error(&err_msg, true, &mut batch); + } + } + return; + } + }; + + let connection = match self.metadata.get_connection(&tablet_server).await { + Ok(conn) => conn, + Err(e) => { + let err_msg = format!("Failed to get connection to server {}: {}", destination, e); + for batches in batches_by_table.into_values() { + for mut batch in batches { + self.handle_lookup_error(&err_msg, true, &mut batch); + } + } + return; + } + }; + + // Send requests for each table + for (table_id, mut batches) in batches_by_table { + // Build the request with all buckets for this table + // Use std::mem::take to move keys instead of cloning to avoid deep copy overhead + let mut all_keys_by_bucket: Vec<(i32, Option<i64>, Vec<Vec<u8>>)> = Vec::new(); Review Comment: Let use respective types, make for easier reading. ########## crates/fluss/src/client/lookup/lookup_client.rs: ########## @@ -0,0 +1,194 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Lookup client that batches multiple lookups together for improved throughput. +//! +//! This client achieves parity with the Java client by: +//! - Queuing lookup operations instead of sending them immediately +//! - Batching multiple lookups to the same server/bucket +//! - Running a background sender task to process batches + +use super::{LookupQuery, LookupQueue}; +use crate::client::lookup::lookup_sender::LookupSender; +use crate::client::metadata::Metadata; +use crate::config::Config; +use crate::error::{Error, Result}; +use crate::metadata::{TableBucket, TablePath}; +use log::{debug, error}; +use std::sync::Arc; +use std::sync::atomic::{AtomicBool, Ordering}; +use std::time::Duration; +use tokio::sync::mpsc; +use tokio::task::JoinHandle; + +/// A client that lookups values from the server with batching support. +/// +/// The lookup client uses a queue and background sender to batch multiple +/// lookup operations together, reducing network round trips and improving +/// throughput. +/// +/// # Example +/// +/// ```ignore +/// let lookup_client = LookupClient::new(config, metadata); +/// let result = lookup_client.lookup(table_path, table_bucket, key_bytes).await?; +/// ``` +pub struct LookupClient { + /// Channel to send lookup requests to the queue + lookup_tx: mpsc::Sender<LookupQuery>, + /// Handle to the sender task + sender_handle: Option<JoinHandle<()>>, + /// Shutdown signal sender + shutdown_tx: mpsc::Sender<()>, + /// Whether the client is closed + closed: AtomicBool, +} + +impl LookupClient { + /// Creates a new lookup client. + pub fn new(config: &Config, metadata: Arc<Metadata>) -> Self { + // Extract configuration values + let queue_size = config.lookup_queue_size; + let max_batch_size = config.lookup_max_batch_size; + let batch_timeout_ms = config.lookup_batch_timeout_ms; + let max_inflight = config.lookup_max_inflight_requests; + let max_retries = config.lookup_max_retries; + + // Create queue and channels + let (queue, lookup_tx, re_enqueue_tx) = + LookupQueue::new(queue_size, max_batch_size, batch_timeout_ms); + + // Create sender + let mut sender = + LookupSender::new(metadata, queue, re_enqueue_tx, max_inflight, max_retries); + + // Create shutdown channel + let (shutdown_tx, mut shutdown_rx) = mpsc::channel(1); + + // Spawn sender task + let sender_handle = tokio::spawn(async move { + tokio::select! { + _ = sender.run() => { + debug!("Lookup sender completed"); + } + _ = shutdown_rx.recv() => { + debug!("Lookup sender received shutdown signal"); + sender.initiate_close(); + } + } + }); + + Self { + lookup_tx, + sender_handle: Some(sender_handle), + shutdown_tx, + closed: AtomicBool::new(false), + } + } + + /// Looks up a value by its primary key. + /// + /// This method queues the lookup operation and returns a future that will + /// complete when the server responds. Multiple lookups may be batched together + /// for improved throughput. + /// + /// # Arguments + /// * `table_path` - The table path + /// * `table_bucket` - The table bucket + /// * `key_bytes` - The encoded primary key bytes + /// + /// # Returns + /// * `Ok(Some(bytes))` - The value bytes if found + /// * `Ok(None)` - If the key was not found + /// * `Err(Error)` - If the lookup fails + pub async fn lookup( + &self, + table_path: TablePath, + table_bucket: TableBucket, + key_bytes: Vec<u8>, + ) -> Result<Option<Vec<u8>>> { + // Check if the client is closed + if self.closed.load(Ordering::Acquire) { + return Err(Error::UnexpectedError { + message: "Lookup client is closed".to_string(), + source: None, + }); + } + + let (result_tx, result_rx) = tokio::sync::oneshot::channel(); + + let query = LookupQuery::new(table_path, table_bucket, key_bytes, result_tx); + + // Send to queue + self.lookup_tx + .send(query) + .await + .map_err(|_| Error::UnexpectedError { + message: "Failed to queue lookup: channel closed".to_string(), Review Comment: Should we log out the details of the failed query? -- This is an automated message from the Apache Git Service. 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