Hi, Вова. Junrui is right. As far as I know, every time a SQL is re-executed, Flink will regenerate the plan, generate jobgraph, and execute the job again. There is no cache to speed up this process. State beckend is used when your job is stopped and you want to continue running from the state before. You can see more here[1].
[1] https://nightlies.apache.org/flink/flink-docs-master/docs/ops/state/state_backends/ -- Best！ Xuyang 在 2024-01-12 12:37:43，"Junrui Lee" <jrlee....@gmail.com> 写道： Hi Вова In Flink, there is no built-in mechanism for caching SQL query results; every query execution is independent, and results are not stored for future queries. The StateBackend's role is to maintain operational states within jobs, such as aggregations or windowing, which is critical for ensuring data consistency and fault tolerance but is unrelated to result caching. Вова Фролов <vovafrolov1...@gmail.com> 于2024年1月11日周四 16:27写道： Hi Everyone, I'm currently looking to understand the caching mechanism in Apache Flink in general. As part of this exploration, I have a few questions related to how Flink handles data caching, both in the context of SQL queries and more broadly. When I send a SQL query for example to PostgreSQL through Flink, does Flink cache the data? If the same SQL query is executed again, does Flink retrieve the results faster, indicating potential caching mechanisms? If caching does occur, where does Flink store the cached data? I'm using RocksDB as a StateBackend. Is there any documentation or information on how Flink caches data during SQL queries when RocksDB is used as a StateBackend? After executing a SQL query, I couldn't find any cached data in local files. Additionally, could you please provide an overview of how the caching mechanism works in Flink in general? I appreciate any insights or references you can provide on this matter. Thank you!
