Implemented parametric VARCHAR #88
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Currently it is hard to calculate length of return type properly for vararg functions.
This patch changes the way optimization for not inserting cast calls for
type-type only coercions work.
Original code caused errors during bytecode preparation for plan execution.
Problematic case:
ARRAY('dog', 'kitten').
During semantic analysis this was treated as:
ARRAY((CAST 'dog' as VARCHAR(6)), 'kitten') and therefore
implementation of ArrayConstructor for parameter type VARCHAR(6) was
generated.
But cast expression was not added to result query expression, as
case VARCHAR(3) -> VARCHAR(6) is type-only cast.
Then byte generating code was failing as it was looking for
instantiation of ARRAY_CONSTRUCTOR(VARCHAR(3), VARCHAR(6)) despite the fact
only ARRAY_CONSTRUCTOR(VARCHAR(6), VARCHAR(6)) was generated.
Now we add Cast operator to AST. But it has typeOnly marker set to true.
And then when execution plan is generated no cast operation call is
generated.
1. relax limitation that when INSERT INTO statement is called values/query types must exactly match table column types. Now we allow values/query types to be type-only coercible to table column types. 2. allow difference between inserted values and table column types if they are type-coercable for structural types.
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This pull request follows prestodb#4005 |
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Superseded by prestodb#4303 |
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