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https://issues.apache.org/jira/browse/CALCITE-5995?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Julian Hyde resolved CALCITE-5995.
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Resolution: Fixed
Fixed in
[1cc1eb3a|https://github.com/apache/calcite/commit/1cc1eb3a477ce7687436024b4760cf1f04a80cbc];
thanks for the PR, [~zhoujira86]!
> Add cache to the dejsonize functions (JSON_VALUE, JSON_EXISTS, JSON_QUERY)
> --------------------------------------------------------------------------
>
> Key: CALCITE-5995
> URL: https://issues.apache.org/jira/browse/CALCITE-5995
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.35.0
> Reporter: xiaogang zhou
> Priority: Minor
> Labels: pull-request-available
> Fix For: 1.36.0
>
>
> I used the json_value function to parse json values. And I found calcite's
> json_value function does not cache the dejsonized objects, which could cause
> some performance issue in situation below as the dejsonize function being
> called repeatedly unnecessarily.
>
> {code:java}
> select
> json_value(A, 'xxx'),
> json_value(A, 'yyy'),
> json_value(A, 'zzz'),...
> from some_table;
> {code}
>
>
> As project like flink uses the json_value to codegen it's own json_value
> function, I think this could cause a bad performance for users. So I suggest
> to introduce a cache in
>
> org.apache.calcite.runtime.JsonFunctions#dejsonize
>
> and the solution is very common in projects like hive
> [https://github.com/apache/hive/blob/storage-branch-2.3/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDTFJSONTuple.java]
>
> and of course, this feature can be turned on only some certain config is
> setted. And if this is acceptable, I think I can take the ticket. thx
>
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