WIP: [Issue-36] Add DateTime64 data type. #38
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clickhouse/columns/date.cpp
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| @@ -113,4 +113,69 @@ ItemView ColumnDateTime::GetItem(size_t index) const { | |||
| return data_->GetItem(index); | |||
| } | |||
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| ColumnDateTime64::ColumnDateTime64() | |||
| : Column(Type::CreateDateTime64(3ul)) | |||
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Maybe we shouldn't provide a default constructor at all or come up with a different default precision. I will be happy to get feedback regarding this line.
clickhouse/columns/date.cpp
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| } | ||
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| Int128 ColumnDateTime64::At(size_t n) const { |
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I Decided to use Int128 because ColumnDecimal deals with this type. Poco supports https://pocoproject.org/docs/Poco.DateTime.html, but DateTime64 in Clickhouse has a higher resolution than in Poco.
| size_t precision = col->Type()->As<DateTime64Type>()->GetPrecision(); | ||
| auto result = std::make_shared<ColumnDateTime64>(precision); // TODO FIXME | ||
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| result->data_->Append(col); |
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Why appending when you can swap?
clickhouse/columns/date.h
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| ColumnDateTime64(size_t); | ||
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| /// Appends one element to the end of column. | ||
| void Append(const Int128& value); |
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I would rather use Int64 here, since it is a bit misleading to put 128-bit int into DateTime64 column
clickhouse/columns/date.h
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| class ColumnDateTime64 : public Column { | ||
| public: | ||
| ColumnDateTime64(); | ||
| ColumnDateTime64(size_t); |
clickhouse/columns/date.h
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| /** */ | ||
| class ColumnDateTime64 : public Column { | ||
| public: | ||
| ColumnDateTime64(); |
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I do not think that having a default precision here is a good thing, can you remove it?
clickhouse/columns/date.h
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| void Append(const std::string& value); | ||
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| /// Returns element at given row number. | ||
| Int128 At(size_t n) const; |
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I guess it makes sense to use Int64 here too.
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| /// Returns element at given row number. | ||
| Int128 At(size_t n) const; | ||
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Please add method GetPrecision() const
| @@ -26,6 +26,7 @@ class Type { | |||
| String, | |||
| FixedString, | |||
| DateTime, | |||
| DateTime64, | |||
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IMO that could break some implicit user assumptions, it is better to add new enum value to the end of the list.
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| ColumnRef ColumnDateTime64::Slice(size_t begin, size_t len) { | ||
| auto col = data_->Slice(begin, len)->As<ColumnDecimal>(); | ||
| size_t precision = col->Type()->As<DateTime64Type>()->GetPrecision(); |
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that would blow up terribly, do you mean col->Type()->As<DecimalType>()->GetPrecision()? Also please add following to the DecimalType:
inline size_t GetPrecision() const { return precision_; }
| @@ -144,6 +147,18 @@ class DecimalType : public Type { | |||
| const size_t precision_, scale_; | |||
| }; | |||
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| class DateTime64Type: public Type { | |||
| public: | |||
| DateTime64Type(size_t precision); | |||
…ers for Decimals and DateTime64
…ers for Decimals and DateTime64
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What's the status of this PR? I would like to use this feature. Is there any way I could contribute or help anyway? |
Going to add tests, and we are good to go.