trinodb/trino

Restrict drop column operations for hive tables

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Aperta il 22 feb 2024

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 (4 commenti) (0 reazioni) (0 assegnatari)Java (9113 star) (2678 fork)batch import
good first issuehive

Descrizione

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.

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Tech stack
javasql
Dominio
backenddatabase
Tipo issue
bug
DifficoltàQuanto dovrebbe essere impegnativa per un nuovo contributor.
3
Tempo stimatoTempo stimato per completare e verificare uno scope piccolo.
1-2 days
Stato attivitàQuanto è probabile che la issue sia ancora attiva e reviewable.
fresh
ChiarezzaQuanto chiaramente la issue descrive problema, scope e risultato atteso.
clear
Prerequisiti
Hive SerDe knowledgeTrino/Hive connector basicsJavaSQL DDL
Adatta ai principiantiQuanto la issue è adatta a contributor alla prima esperienza.
45
Direzione di ricerca
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.