trinodb/trino

Restrict drop column operations for hive tables

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#20,807 创建于 2024年2月22日

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 (4 评论) (0 反应) (0 负责人)Java (9,113 star) (2,678 fork)batch import
good first issuehive

描述

As per the Hive docs - https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-AlterTable/Partition/Column

REPLACE COLUMNS removes all existing columns and adds the new set of columns. This can be done only for tables with a native SerDe (DynamicSerDe, MetadataTypedColumnsetSerDe, LazySimpleSerDe and ColumnarSerDe). Refer to Hive SerDe for more information. REPLACE COLUMNS can also be used to drop columns. For example, "ALTER TABLE test_change REPLACE COLUMNS (a int, b int);" will remove column 'c' from test_change's schema.

But we try to run replace columns operation for all the file formats which provides inconsistent behavior both from Trino's hive connector and querying hive directly.

贡献者指南

技术栈
javasql
领域
backenddatabase
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-2 days
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
fresh
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
Hive SerDe knowledgeTrino/Hive connector basicsJavaSQL DDL
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
45
研究方向
Investigate the Hive connector's ALTER TABLE implementation in Trino, specifically the code path for REPLACE COLUMNS. Identify where the operation is currently permitted for all file formats. Add a check to restrict the operation to tables using native SerDe types (DynamicSerDe, MetadataTypedColumnsetSerDe, LazySimpleSerDe, ColumnarSerDe). Reference the Hive documentation linked in the issue and consider testing with various file formats. Consult any comments in the issue for additional context or maintainer guidance.