CheckOverflowInTableInsert¶

Overview¶

The CheckOverflowInTableInsert expression is a wrapper that captures arithmetic overflow errors during numeric casting operations in table insert scenarios. It provides enhanced error messages that include the source and target data types along with the column name where the overflow occurred, making debugging easier for users.

Syntax¶

This expression is not directly accessible through SQL syntax. It's an internal Catalyst expression used by Spark's query planner to wrap cast operations during table insertions.

// Internal usage in Catalyst
CheckOverflowInTableInsert(castExpression, columnName)

Arguments¶

Argument	Type	Description
child	Expression	The underlying expression (typically a Cast) that may cause overflow
columnName	String	The name of the target column for error reporting

Return Type¶

Returns the same data type as the child expression (child.dataType).

Supported Data Types¶

Supports all data types that the underlying child expression supports, but is primarily designed for numeric casting operations where overflow can occur:

Byte, Short, Integer, Long
Float, Double
Decimal types
Any other data types supported by the wrapped expression

Algorithm¶

Executes the child expression normally during evaluation
Catches any SparkArithmeticException thrown by the child expression
If the child is a Cast operation, throws an enhanced error message with source type, target type, and column name
If the child is not a Cast, re-throws the original exception
For code generation, wraps the child's generated code in a try-catch block with enhanced error handling

Partitioning Behavior¶

This expression preserves the partitioning behavior of its child expression:

Does not affect partitioning directly as it's a wrapper expression
Partitioning behavior depends entirely on the wrapped child expression
No additional shuffle operations are introduced

Edge Cases¶

Null handling: Preserves the null handling behavior of the child expression
Non-Cast children: When wrapping non-Cast expressions, falls back to standard error handling
Proxy expressions: Handles ExpressionProxy wrappers around Cast expressions
Overflow detection: Only catches SparkArithmeticException, allowing other exceptions to propagate normally
Error message enhancement: Only provides enhanced error messages when the child is identifiable as a Cast operation

Code Generation¶

Supports full code generation (Tungsten):

Generates optimized code when the child is a Cast expression
Wraps the child's generated code in a try-catch block
Includes proper null handling in generated code
Falls back to child's code generation for non-Cast expressions
Uses CodegenContext to manage object references for data types and column names

Examples¶

-- This expression is used internally during operations like:
INSERT INTO target_table (numeric_column) 
SELECT large_value FROM source_table;
-- When large_value causes overflow in numeric_column

// Internal Catalyst usage (not user-facing)
val castExpr = Cast(child = largeIntExpr, dataType = ByteType)
val safeExpr = CheckOverflowInTableInsert(castExpr, "target_column")