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Posted to issues@spark.apache.org by "Kent Yao (Jira)" <ji...@apache.org> on 2022/08/01 08:21:00 UTC

[jira] [Created] (SPARK-39930) Cache Hints

Kent Yao created SPARK-39930:
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             Summary: Cache Hints
                 Key: SPARK-39930
                 URL: https://issues.apache.org/jira/browse/SPARK-39930
             Project: Spark
          Issue Type: New Feature
          Components: SQL
    Affects Versions: 3.4.0
            Reporter: Kent Yao


This ticket intends to add query hints for cache behaviors, user can perform actions like the use/skip/cache/uncache, etc on the cached results by the following hints.

 

- RESULT_CACHE

 spark will use cache by default, this hint keep this behavior but will cache the child plan if uncached yet.

- NO_RESULT_CACHE

with this hint, we can skip the default behavior to by pass the cached data if it is cache

- RESULT_UNCACHE

with this hint, we can remove the cached data.

 

RESULT_CACHE and NO_RESULT_CACHE are borrowed from oracle, FYI,

[https://docs.oracle.com/database/121/TGDBA/tune_result_cache.htm#TGDBA647.|https://docs.oracle.com/database/121/TGDBA/tune_result_cache.htm#TGDBA647]

RESULT_UNCACHE's added accordingly.

 

Similar ideas can also be found in MySQL, FYI [https://dev.mysql.com/doc/refman/5.7/en/query-cache-in-select.html]

 

Maybe we can add more cache hints like RESULT_RECACHE to refresh the cached data, or maybe some cache behaviors that relate to metadata.

 



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