HuangZhenQiu commented on code in PR #19046: URL: https://github.com/apache/hudi/pull/19046#discussion_r3562735890
########## rfc/rfc-107/rfc-107.md: ########## @@ -0,0 +1,306 @@ + <!-- + 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. +--> +# RFC-107: Dynamic Partitioned Cache for Flink Hudi Upsert + +## Proposers + +- @zhenqiu-huang + +## Approvers + - TBD + +## Status + - In Progress + +## Abstract + +[RFC-106](../rfc-106/rfc-106.md) introduces Record Level Index (RLI) support for Flink streaming writes, including a simple in-memory cache for index lookups in the `BucketAssigner` operator. While the in-memory cache works well for small to moderate workloads, it faces scalability challenges for large tables with billions of records: the cache either consumes excessive JVM heap memory or suffers from high eviction rates that degrade lookup performance. +In modern CloudLake systems that rely on object storage platforms such as GCS, OCI Object Storage, and Amazon S3, data is typically transitioned to lower storage tiers over time to optimize storage costs. However, using an in-memory cache to accelerate index lookups may result in increased data processing overhead. + +This RFC proposes a **Dynamic Partitioned Cache** backed by RocksDB that serves as a local materialized replica of the MDT RLI. The cache provides: + +- **O(1) local lookups** for record location resolution during streaming writes, eliminating per-record MDT I/O Review Comment: To make the flink ingestion continuously run, we probably don't do clustering on MOR table. But still If there is data rewrite needs for data security concern, we probably need to consider a policy to minimize the concurrent writer on partitions. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
