trinodb/trino

Restrict drop column operations for hive tables

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#20,807 建立於 2024年2月22日

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 (4 留言) (0 反應) (0 負責人)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.

貢獻者指南

技術棧
javasql
領域
backenddatabase
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-2 days
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
fresh
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
Hive SerDe knowledgeTrino/Hive connector basicsJavaSQL DDL
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
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.