Details
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Bug
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Status: Closed
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Minor
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Resolution: Fixed
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1.34.0
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None
Description
Supplying arguments that are out-of-bounds for functions can produce uninformative messages. Consider this test case that can be added to SqlOperatorTest.checkSubstringFunction():
f.checkString("substring('abc' from 2 for 2147483650)",
"bc", "VARCHAR(3) NOT NULL");
The signature of the substring function requires int arguments. The constant 2147483650 is out of bounds for an integer. This causes the test to fail with the following exception:
Error while executing SQL "values (substring('abc' from 2 for 2147483650))": Unable to implement EnumerableCalc(expr#0=[{inputs}], expr#1=['abc'], expr#2=[2], expr#3=[2147483650:BIGINT], expr#4=[SUBSTRING($t1, $t2, $t3)], EXPR$0=[$t4]): rowcount = 1.0, cumulative cost = {2.0 rows, 7.0 cpu, 0.0 io}, id = 153424 EnumerableValues(tuples=[[{ 0 }]]): rowcount = 1.0, cumulative cost = {1.0 rows, 1.0 cpu, 0.0 io}, id = 153408
I suspect this happens because of a combination of features:
- type inference does not reject the call to substring, although the inferred type of the argument is probably bigint
- an attempt to evaluate the constant function fails because of some overflow
- the detailed exception about the overflow is lost when handling the error
I suspect this is a deeper problem which may affect all functions, and it is really about type inference and implicit cast insertion.
I can imagine two possible implementation strategies:
- Postgres rejects such a call because the substring function cannot take a bigint argument
- The compiler could add an implicit cast from bigint to int, which should at least give a warning because the value is too large to fit in an integer
Both these solutions would avoid a crash in the expression evaluation. I personally do not yet understand well enough the type inference mechanisms in Calcite to propose a solution.
To make matters worse, some SQL dialects have substring functions with bigint arguments. In this case there should be two different substring functions, with different signatures.
This issue surfaced during a discussion for https://github.com/apache/calcite/pull/3286, and is related to https://issues.apache.org/jira/browse/CALCITE-5810.