[GitHub] [incubator-doris] xinghuayu007 opened a new issue #6631: [Feature] Support Hedged Request to handle slow scan node

[GitBox <gi...@apache.org>]

xinghuayu007 opened a new issue #6631:
URL: https://github.com/apache/incubator-doris/issues/6631


   ### Search before asking
   
   - [X] I had searched in the [issues](https://github.com/apache/incubator-doris/issues?q=is%3Aissue) and found no similar issues.
   
   
   ### Description
   
   A query may need to scan data from many nodes. If one node scans data very slowly, It will delay the whole query. As no resource isolation in Doris, one node will become `Slow Node` very common because of high cpu load or memory exhaustion.   For the users, they find the same query finished with different time cost. On the other hand, as no `Fail Tolerant`, for a big query, a node failed  will cause the whole query failed. It will cost a lot time to begin a new query.
   
   In a word, a slow node or failed node will delay the whole query. How to solve this problem?
   
   **Hedged Request** is a method to handle long tail problem. Very time, it will create multiple queries to different replications. It chooses the first one fasted returned query and cancel other queries. It only need another more than 5% load to assure the request stable. 
   
   Doris hash many replications for one table. Therefore,  Hedged Request can be implemented in Doris to make query stable. That is important for Real-Time BI Report. 
   
   ### Use case
   
   This feature is suitable for users who want stable query performance.
   
   ### Related issues
   
   _No response_
   
   ### Are you willing to submit PR?
   
   - [X] Yes I am willing to submit a PR!
   
   ### Code of Conduct
   
   - [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)
   


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