[CALCITE-583] Operator `||` mishandled ANY type

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.1.0-incubating
• Assignee: Julian Hyde
• Reporter: Sean Hsuan-Yi Chu
• Created: 01/Feb/15 22:17
• Updated: 23/Mar/15 08:08
• Resolved: 10/Feb/15 06:53

Description

For instance,
select ANY type || ANY type ... leads assertion error from:
assert (precision >= 0) || (precision == RelDataType.PRECISION_NOT_SPECIFIED);
(SqlTypeFactoryImpl.java( line: 62))

Essentially, it is because, SqlReturnTypeInference of `||` is DYADIC_STRING_SUM_PRECISION. When doing inference for the return type, there is one data field in DYADIC_STRING_SUM_PRECISION called "precision", which is calculated as arg0.precison + arg1.precision.

However, for ANY type, the precision is defined as -1. So the above calculation will give "-2" for ANY type operands, in turn, breaking up the assertion.

Moreover, `||` can fail when the two operands have different types (e.g., ANY type || String). In the No schema system, ANY type can be quite prevalent. For example, select ANY type || string || ANY type ... where, in addition to two ANY types on two sides, we have a string in between.