```
ubuntu@ip-172-31-79-147:/opt/downloads$ clickhouse-local --max_threads 8 --query "WITH parseDateTimeBestEffort(extract(_path, 'pageviews-([\\d\\-]+)\\.gz$')) AS time, splitByChar(' ', line) AS values, splitByChar('.', values[1]) AS projects SELECT time, projects[1] AS project, projects[2] AS subproject, values[2] AS path, (values[3])::UInt64 AS hits FROM file('pageviews*.gz', LineAsString) WHERE length(values) >= 3" | pv > /dev/null
^C01GiB 0:01:08 [ 129MiB/s] [                                                                                                                                                                   <=>                                                                                    ]

ubuntu@ip-172-31-79-147:/opt/downloads$ clickhouse-local --max_threads 8 --query "WITH parseDateTimeBestEffort(extract(toLowCardinality(_path), 'pageviews-([\\d\\-]+)\\.gz$')) AS time, splitByChar(' ', line) AS values, splitByChar('.', values[1]) AS projects SELECT time, projects[1] AS project, projects[2] AS subproject, values[2] AS path, (values[3])::UInt64 AS hits FROM file('pageviews*.gz', LineAsString) WHERE length(values) >= 3" | pv > /dev/null
^C46GiB 0:00:48 [ 175MiB/s] [                                                                                                                                                                                                                                        <=>               ]
```

{
private:
    DataTypePtr dictionary_type;
public:
    DataTypeLowCardinality(DataTypePtr dictionary_type_);
    const DataTypePtr & getDictionaryType() const { return dictionary_type; }
    String doGetName() const override
    {
        return "LowCardinality(" + dictionary_type->getName() + ")";
    }
    const char * getFamilyName() const override { return "LowCardinality"; }
    TypeIndex getTypeId() const override { return TypeIndex::LowCardinality; }
    MutableColumnPtr createColumn() const override;
    Field getDefault() const override;
    bool equals(const IDataType & rhs) const override;
    bool isParametric() const override { return true; }
    bool haveSubtypes() const override { return true; }
    bool cannotBeStoredInTables() const override { return dictionary_type->cannotBeStoredInTables(); }
    bool shouldAlignRightInPrettyFormats() const override { return dictionary_type->shouldAlignRightInPrettyFormats(); }
    bool textCanContainOnlyValidUTF8() const override { return dictionary_type->textCanContainOnlyValidUTF8(); }
    bool isComparable() const override { return dictionary_type->isComparable(); }
    bool canBeComparedWithCollation() const override { return dictionary_type->canBeComparedWithCollation(); }
    bool canBeUsedAsVersion() const override { return dictionary_type->canBeUsedAsVersion(); }
    bool isSummable() const override { return dictionary_type->isSummable(); }
    bool canBeUsedInBitOperations() const override { return dictionary_type->canBeUsedInBitOperations(); }
    bool canBeUsedInBooleanContext() const override { return dictionary_type->canBeUsedInBooleanContext(); }
    bool isValueRepresentedByNumber() const override { return dictionary_type->isValueRepresentedByNumber(); }
    bool isValueRepresentedByInteger() const override { return dictionary_type->isValueRepresentedByInteger(); }
    bool isValueUnambiguouslyRepresentedInContiguousMemoryRegion() const override { return true; }