+1 Best Regards, - He Xiaoqiao
On Fri, Feb 14, 2025 at 3:53 PM Ayush Saxena <ayush...@gmail.com> wrote: > +1 > > -Ayush > > > On 14 Feb 2025, at 1:20 PM, Hui Fei <feihui.u...@gmail.com> wrote: > > > > Did some test work referring to the documentation. > > > > - Compiled source codes, built a local cluster and the async feature > > worked fine. > > - it is disabled by default > > - can increase or decrease the thread number by changing the related > > configurations > > > > +1 > > > > jian zhang <keeprom...@apache.org> 于2025年2月14日周五 15:21写道： > > > >> Hi, all, the development of the asynchronous router functionality has > been > >> completed. Thanks to all the contributors who participated in this > feature. > >> The development branch is HDFS-17531, and it is ready to be merged into > the > >> trunk branch. > >> > >> JIRA: HDFS-17531 https://issues.apache.org/jira/browse/HDFS-17531 > >> PR: https://github.com/apache/hadoop/pull/7308 > >> > >> DISCUSS: > https://lists.apache.org/thread/02y3dtpfxt21bxjgmyl3kxnv4m1vwz44 > >> > >> Here is the functionality introduction of the asynchronous router for > >> everyone to review: > >> I. Overview > >> > >> The asynchronous router aims to address the performance bottleneck > >> issues of the synchronous router in high - concurrency and multi - > >> nameservices scenarios. By introducing an asynchronous processing > >> mechanism, it optimizes the request handling process, improves the > system's > >> concurrency ability and resource utilization, and is particularly > suitable > >> for the federated scenarios where multiple downstream services (NS) > need to > >> be processed. > >> > >> II. Problems of the Synchronous Router > >> > >> - Performance Bottleneck: The performance of the synchronous router > is > >> limited by the number of handler threads. Even if the connection thread > can > >> still forward requests to the downstream namenode, the handler must wait > >> for each request to complete before processing the next one, resulting > in > >> limited processing capacity. > >> - Thread Resource Waste: To improve performance, increasing the > number > >> of handler threads will lead to more thread switches, which instead > reduces > >> the system efficiency. At the same time, a large number of handler > threads > >> are in a blocked state, wasting thread resources. > >> - Poor Isolation in Multi - ns: If the performance of a certain > >> nameservice in the downstream nameservice is poor, it will cause the > >> handler to wait for a long time, thus affecting the forwarding of > requests > >> to other normal - performance ns, resulting in a decrease in the overall > >> performance of the downstream ns services perceived by the client. > >> - Ineffective Utilization of Federation Multi - ns Performance: In > >> high - concurrency scenarios, a large number of requests may be > backlogged > >> in the router's request queue, while the queues of downstream services > are > >> not fully utilized, leading to unreasonable resource allocation. > >> > >> III. Design and Improvements of the Asynchronous Router > >> > >> The asynchronous router solves the above problems by redesigning the > >> request handling process and introducing an asynchronous processing > >> mechanism. Its core improvements include: > >> > >> - Handler: Retrieves requests from the request queue for preliminary > >> processing. If there are exceptions in the request (such as the mount > point > >> does not exist, etc.), it directly puts the response into the response > >> queue; otherwise, it sends the request to the asynchronous handler > thread > >> pool. > >> - Async Handler: Puts the request into the call queue > >> (connection.calls) of the connection thread and returns immediately > without > >> blocking and waiting. > >> - Async Responder: Is responsible for processing the responses > >> received by the connection thread. If the request needs to be re - > >> initiated (such as the downstream service returns a standby exception), > it > >> re - adds the request to the asynchronous handler thread pool; > otherwise, > >> it puts the response into the response queue. > >> - Responder: Retrieves the response from the response queue and > >> returns it to the client. > >> > >> IV. Advantages of the Asynchronous Router > >> > >> - High - Concurrency Performance: Through the asynchronous processing > >> mechanism, the asynchronous router can handle a large number of requests > >> simultaneously, significantly improving the system's concurrent > processing > >> ability. > >> - High Resource Utilization: It avoids thread blocking and frequent > >> switching, reduces thread resource waste, and improves the overall > >> efficiency of the system. > >> - Isolation: Different ns are processed by different async handler > >> thread pools, achieving isolation of different downstream services. > Even if > >> the performance of a certain service is poor, it will not affect the > >> processing ability of other services. > >> > >> V. Summary > >> > >> The asynchronous router solves the performance bottleneck problem of > >> the traditional synchronous router in high - concurrency scenarios by > >> introducing an asynchronous processing mechanism. It not only improves > the > >> system's concurrency ability and resource utilization but also achieves > >> isolation of downstream services through the queue mechanism, enhancing > the > >> system's stability and adaptability. In the federated scenarios where > >> multiple downstream services need to be processed, the asynchronous > router > >> is a more efficient and reliable solution. > >> VI. Performance Testing > >> > >> > >> > https://docs.google.com/document/d/1meHOCvhm3XRHlIMwvKFidfUSjveTJrb8yAMasrM_HrY/edit?tab=t.0#heading=h.du0zlo2k5sb1 > >> > >> VII. JIRA & RPs > >> > >> For more information, please refer to JIRA: > >> JIRA: RBF: Asynchronous router RPC: > >> https://issues.apache.org/jira/browse/HDFS-17531 > >> PRs: > >> HDFS-17543. [ARR] AsyncUtil makes asynchronous code more concise and > >> easier. > >> HADOOP-19235. IPC client uses CompletableFuture to support > >> asynchronous operations. > >> HDFS-17544. [ARR] The router client rpc protocol PB supports > >> asynchrony. > >> HDFS-17545. [ARR] router async rpc client. > >> HDFS-17594. [ARR] RouterCacheAdmin supports asynchronous rpc. > >> HDFS-17597. [ARR] RouterSnapshot supports asynchronous rpc. > >> HDFS-17595. [ARR] ErasureCoding supports asynchronous rpc. > >> HDFS-17601. [ARR] RouterRpcServer supports asynchronous rpc. > >> HDFS-17596. [ARR] RouterStoragePolicy supports asynchronous rpc. > >> HDFS-17656. [ARR] RouterNamenodeProtocol and RouterUserProtocol > >> supports asynchronous rpc. > >> HDFS-17659. [ARR]Router Quota supports asynchronous rpc. > >> HDFS-17672. [ARR] Move asynchronous related classes to the async > >> package. > >> HADOOP-19361. RPC DeferredMetrics bugfix. > >> HDFS-17640.[ARR] RouterClientProtocol supports asynchronous rpc. > >> HDFS-17650. [ARR] The router server-side rpc protocol PB supports > >> asynchrony. > >> HDFS-17651.[ARR] Async handler executor isolation. > >> HDFS-17715. [ARR] Add documentation for asynchronous router. > >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org > For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org > >
