[SPARK-58554][SQL] Block MySQL double cast pushdown - #57756
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MariaDB rejects CAST(... AS DOUBLE PRECISION). Stop pushing DoubleType casts in MySQLDialect so Spark evaluates them locally instead.
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The dialect-local fallback is narrowly scoped, uses the existing unsupported-expression path, and is covered at both unit and integration levels.
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The MySQL builder delegates every non-DoubleType cast to the shared JDBC implementation. For DoubleType, it throws inside expression compilation; MySQLDialect.compileExpression catches the non-fatal failure and returns None, so the JDBC V2 scan leaves the filter for Spark evaluation. The added tests cover both that compilation result and the end-to-end local-filter behavior.
PR description suggestions
- Clarify the user-facing change: affected MySQL/MariaDB queries now fall back to Spark evaluation and succeed instead of sending an invalid
DOUBLE PRECISIONcast to the database.
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MariaDB rejects CAST(... AS DOUBLE PRECISION). Stop pushing DoubleType casts in MySQLDialect so Spark evaluates them locally instead. ### What changes were proposed in this pull request? Block pushdown of cast to DOUBLE. Without this fix I got the error ``` [JDBC_EXTERNAL_ENGINE_SYNTAX_ERROR.DURING_QUERY_EXECUTION] JDBC external engine syntax error. The error was caused by the query SELECT `name` FROM `employee` WHERE (`salary` IS NOT NULL) AND (CAST(`salary` AS DOUBLE PRECISION) > 10000.5) . (conn=584) You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'PRECISION) > 10000.5)' at line 1. The error occurred during query execution. SQLSTATE: 42000 ``` ### Why are the changes needed? Fix a wrong query. ### Does this PR introduce _any_ user-facing change? No. ### How was this patch tested? Added tests. ### Was this patch authored or co-authored using generative AI tooling? Generated-by: Opus 5 Closes #57756 from alekjarmov/alekjarmov/block-mysql-double-cast-pushdown. Authored-by: Alek Jarmov <alek.jarmov@databricks.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com> (cherry picked from commit 00ea1ab) Signed-off-by: Wenchen Fan <wenchen@databricks.com>
cloud-fan
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Aug 4, 2026
MariaDB rejects CAST(... AS DOUBLE PRECISION). Stop pushing DoubleType casts in MySQLDialect so Spark evaluates them locally instead. ### What changes were proposed in this pull request? Block pushdown of cast to DOUBLE. Without this fix I got the error ``` [JDBC_EXTERNAL_ENGINE_SYNTAX_ERROR.DURING_QUERY_EXECUTION] JDBC external engine syntax error. The error was caused by the query SELECT `name` FROM `employee` WHERE (`salary` IS NOT NULL) AND (CAST(`salary` AS DOUBLE PRECISION) > 10000.5) . (conn=584) You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'PRECISION) > 10000.5)' at line 1. The error occurred during query execution. SQLSTATE: 42000 ``` ### Why are the changes needed? Fix a wrong query. ### Does this PR introduce _any_ user-facing change? No. ### How was this patch tested? Added tests. ### Was this patch authored or co-authored using generative AI tooling? Generated-by: Opus 5 Closes #57756 from alekjarmov/alekjarmov/block-mysql-double-cast-pushdown. Authored-by: Alek Jarmov <alek.jarmov@databricks.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com> (cherry picked from commit 00ea1ab) Signed-off-by: Wenchen Fan <wenchen@databricks.com>
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MariaDB rejects CAST(... AS DOUBLE PRECISION). Stop pushing DoubleType casts in MySQLDialect so Spark evaluates them locally instead.
What changes were proposed in this pull request?
Block pushdown of cast to DOUBLE. Without this fix I got the error
Why are the changes needed?
Fix a wrong query.
Does this PR introduce any user-facing change?
No.
How was this patch tested?
Added tests.
Was this patch authored or co-authored using generative AI tooling?
Generated-by: Opus 5