fix: PostgreSQL dialect can not support tinyint type#21445
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metegenez merged 2 commits intoapache:mainfrom Apr 10, 2026
Merged
fix: PostgreSQL dialect can not support tinyint type#21445metegenez merged 2 commits intoapache:mainfrom
metegenez merged 2 commits intoapache:mainfrom
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Thanks for the work. LGTM. Just adding 1 more test to clear the air would be great.
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We can add a test that the default path still produces TINYINT, just for reference and degradation prevention.
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LGTM. If this does no break any upstream feature, we can merge it. Let's wait a bit for additional reviews.
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@metegenez Hi, Do we still need to wait a while longer? |
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@metegenez Thanks for your review! |
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Which issue does this PR close?
Rationale for this change
DataFusion's PostgreSQL unparser should emit PostgreSQL-compatible SQL for integer casts.
Int8was still being rendered asTINYINT, which is not valid PostgreSQL syntax. This change makes PostgreSQL outputSMALLINTinstead.What changes are included in this PR?
int8_cast_dtypehook to the SQL unparser dialect abstraction.PostgreSqlDialectto mapInt8toSMALLINT.DataType::Int8unparsing through the dialect hook.select cast(3 as tinyint)]with PostgreSQL unparser output.Are these changes tested?
cargo test -p datafusion-sql --test sql_integration cases::plan_to_sql::test_cast_to_tinyint -- --exactAre there any user-facing changes?
CAST(... AS SMALLINT)forInt8values instead ofCAST(... AS TINYINT).