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Better implementation

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This commit is contained in:
avogar 2024-07-25 18:59:06 +00:00
parent f00928afa1
commit eb300f4f78
1 changed files with 24 additions and 32 deletions
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56
src/Functions/FunctionsConversion.cpp
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@ -4078,6 +4078,26 @@ private:
};
}
/// Create wrapper only if we support this conversion.
WrapperType createWrapperIfCanConvert(const DataTypePtr & from, const DataTypePtr & to) const
{
try
{
/// We can avoid try/catch here if we will implement check that 2 types can be casted, but it
/// requires quite a lot of work. By now let's simply use try/catch.
/// First, check that we can create a wrapper.
WrapperType wrapper = prepareUnpackDictionaries(from, to);
/// Second, check if we can perform a conversion on empty columns.
ColumnsWithTypeAndName column_from = {{from->createColumn(), from, "" }};
wrapper(column_from, to, nullptr, 0);
return wrapper;
}
catch (...)
{
return {};
}
}
WrapperType createVariantToColumnWrapper(const DataTypeVariant & from_variant, const DataTypePtr & to_type) const
{
const auto & variant_types = from_variant.getVariants();
@ -4090,17 +4110,8 @@ private:
WrapperType wrapper;
if (cast_type == CastType::accurateOrNull)
{
/// With accurateOrNull cast type we should insert default values on variants that cannot be casted.
/// We can avoid try/catch here if we will implement check that 2 types can be casted, but it
/// requires quite a lot of work. By now let's simply use try/catch.
try
{
wrapper = prepareUnpackDictionaries(variant_type, to_type);
}
catch (...)
{
/// Leave wrapper empty and check it later.
}
/// Create wrapper only if we support conversion from variant to the resulting type.
wrapper = createWrapperIfCanConvert(variant_type, to_type);
}
else
{
@ -4109,7 +4120,7 @@ private:
variant_wrappers.push_back(wrapper);
}
return [variant_wrappers, variant_types, to_type, cast_type_ = this->cast_type]
return [variant_wrappers, variant_types, to_type]
(ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, const ColumnNullable *, size_t input_rows_count) -> ColumnPtr
{
const auto & column_variant = assert_cast<const ColumnVariant &>(*arguments.front().column.get());
@ -4125,26 +4136,7 @@ private:
ColumnPtr casted_variant;
/// Check if we have wrapper for this variant.
if (variant_wrapper)
{
if (cast_type_ == CastType::accurateOrNull)
{
/// With accurateOrNull cast type wrapper should throw an exception
/// only when the cast between types is not supported.
/// In this case we will insert default values on rows with this variant.
try
{
casted_variant = variant_wrapper(variant, result_type, nullptr, variant_col->size());
}
catch (...)
{
/// Do nothing.
}
}
else
{
casted_variant = variant_wrapper(variant, result_type, nullptr, variant_col->size());
}
}
casted_variant = variant_wrapper(variant, result_type, nullptr, variant_col->size());
casted_variant_columns.push_back(std::move(casted_variant));
}