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https://issues.apache.org/jira/browse/FLINK-21998?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jark Wu closed FLINK-21998.
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Assignee: Rui Li
Resolution: Fixed
Fixed in master: 5045ac18f55e6a794da67e4c68d0d87cec4f9a57
> Copy more code from hive and move them to a dedicated package
> -------------------------------------------------------------
>
> Key: FLINK-21998
> URL: https://issues.apache.org/jira/browse/FLINK-21998
> Project: Flink
> Issue Type: Sub-task
> Components: Connectors / Hive
> Reporter: Rui Li
> Assignee: Rui Li
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.13.0
>
>
> As discussed in
> [FLIP-152|https://cwiki.apache.org/confluence/display/FLINK/FLIP-152%3A+Hive+Query+Syntax+Compatibility]:
> In order to support multiple Hive versions, we keep our own copy of Hive code
> to generate the ASTNode and do semantic analysis. This means that a SQL
> statement is processed with the same code no matter which Hive version is in
> use. The rationale behind this decision is:
> 1. HiveQL syntax is in general backward compatible. So we can use a newer
> version to support older versions.
> 2. The process to generate RelNode plan is tightly coupled with ASTNode and
> semantic analysis. While it’s theoretically possible to make
> HiveParserCalcitePlanner support different versions, that’ll make the logic
> much more complicated and error-prone.
> 3. The copied code gives us more flexibility to support new features in the
> future. For example, we can adapt the code to support writing HiveQL for
> generic tables, or support querying tables across multiple catalogs.
> Since most Hive users are still using Hive 2.x or 1.x, we'll copy Hive code
> from 2.x, which would reduce the required efforts to cover these versions.
> For new features in Hive 3.x, e.g. table constraints, we'll extend the copied
> code to support them.
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