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41cdedbf26
ClickHouse/src/Functions/FunctionGenerateRandomStructure.cpp
Robert Schulze 8896134531
Cleanup IDataType convenience functions
2023-11-06 13:25:32 +00:00

447 lines
16 KiB
C++
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#include <Functions/FunctionGenerateRandomStructure.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <Functions/IFunction.h>
#include <Columns/ColumnString.h>
#include <DataTypes/DataTypeString.h>
#include <DataTypes/DataTypeFixedString.h>
#include <Interpreters/Context.h>
#include <Common/randomSeed.h>
#include <Common/FunctionDocumentation.h>
#include <IO/WriteHelpers.h>
#include <IO/WriteBufferFromVector.h>
#include <pcg_random.hpp>
namespace DB
{
namespace ErrorCodes
{
extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int BAD_ARGUMENTS;
}
namespace
{
const size_t MAX_NUMBER_OF_COLUMNS = 128;
const size_t MAX_TUPLE_ELEMENTS = 16;
const size_t MAX_DATETIME64_PRECISION = 9;
const size_t MAX_DECIMAL32_PRECISION = 9;
const size_t MAX_DECIMAL64_PRECISION = 18;
const size_t MAX_DECIMAL128_PRECISION = 38;
const size_t MAX_DECIMAL256_PRECISION = 76;
const size_t MAX_DEPTH = 16;
constexpr std::array<TypeIndex, 29> simple_types
{
TypeIndex::Int8,
TypeIndex::UInt8,
TypeIndex::Int16,
TypeIndex::UInt16,
TypeIndex::Int32,
TypeIndex::UInt32,
TypeIndex::Int64,
TypeIndex::UInt64,
TypeIndex::Int128,
TypeIndex::UInt128,
TypeIndex::Int256,
TypeIndex::UInt256,
TypeIndex::Float32,
TypeIndex::Float64,
TypeIndex::Decimal32,
TypeIndex::Decimal64,
TypeIndex::Decimal128,
TypeIndex::Decimal256,
TypeIndex::Date,
TypeIndex::Date32,
TypeIndex::DateTime,
TypeIndex::DateTime64,
TypeIndex::String,
TypeIndex::FixedString,
TypeIndex::Enum8,
TypeIndex::Enum16,
TypeIndex::IPv4,
TypeIndex::IPv6,
TypeIndex::UUID,
};
constexpr std::array<TypeIndex, 5> complex_types
{
TypeIndex::Nullable,
TypeIndex::LowCardinality,
TypeIndex::Array,
TypeIndex::Tuple,
TypeIndex::Map,
};
constexpr std::array<TypeIndex, 22> map_key_types
{
TypeIndex::Int8,
TypeIndex::UInt8,
TypeIndex::Int16,
TypeIndex::UInt16,
TypeIndex::Int32,
TypeIndex::UInt32,
TypeIndex::Int64,
TypeIndex::UInt64,
TypeIndex::Int128,
TypeIndex::UInt128,
TypeIndex::Int256,
TypeIndex::UInt256,
TypeIndex::Date,
TypeIndex::Date32,
TypeIndex::DateTime,
TypeIndex::String,
TypeIndex::FixedString,
TypeIndex::IPv4,
TypeIndex::Enum8,
TypeIndex::Enum16,
TypeIndex::UUID,
TypeIndex::LowCardinality,
};
constexpr std::array<TypeIndex, 22> suspicious_lc_types
{
TypeIndex::Int8,
TypeIndex::UInt8,
TypeIndex::Int16,
TypeIndex::UInt16,
TypeIndex::Int32,
TypeIndex::UInt32,
TypeIndex::Int64,
TypeIndex::UInt64,
TypeIndex::Int128,
TypeIndex::UInt128,
TypeIndex::Int256,
TypeIndex::UInt256,
TypeIndex::Float32,
TypeIndex::Float64,
TypeIndex::Date,
TypeIndex::Date32,
TypeIndex::DateTime,
TypeIndex::String,
TypeIndex::FixedString,
TypeIndex::IPv4,
TypeIndex::IPv6,
TypeIndex::UUID,
};
template <bool allow_complex_types>
constexpr auto getAllTypes()
{
constexpr size_t complex_types_size = complex_types.size() * allow_complex_types;
constexpr size_t result_size = simple_types.size() + complex_types_size;
std::array<TypeIndex, result_size> result;
size_t index = 0;
for (size_t i = 0; i != simple_types.size(); ++i, ++index)
result[index] = simple_types[i];
for (size_t i = 0; i != complex_types_size; ++i, ++index)
result[index] = complex_types[i];
return result;
}
size_t generateNumberOfColumns(pcg64 & rng)
{
return rng() % MAX_NUMBER_OF_COLUMNS + 1;
}
void writeLowCardinalityNestedType(pcg64 & rng, WriteBuffer & buf, bool allow_suspicious_lc_types)
{
bool make_nullable = rng() % 2;
if (make_nullable)
writeCString("Nullable(", buf);
if (allow_suspicious_lc_types)
{
TypeIndex type = suspicious_lc_types[rng() % suspicious_lc_types.size()];
if (type == TypeIndex::FixedString)
writeString("FixedString(" + std::to_string(rng() % MAX_FIXEDSTRING_SIZE_WITHOUT_SUSPICIOUS + 1) + ")", buf);
else
writeString(magic_enum::enum_name<TypeIndex>(type), buf);
}
else
{
/// Support only String and FixedString.
if (rng() % 2)
writeCString("String", buf);
else
writeString("FixedString(" + std::to_string(rng() % MAX_FIXEDSTRING_SIZE_WITHOUT_SUSPICIOUS + 1) + ")", buf);
}
if (make_nullable)
writeChar(')', buf);
}
void writeEnumValues(const String & column_name, pcg64 & rng, WriteBuffer & buf, ssize_t max_value)
{
/// Don't generate big enums, because it will lead to really big result
/// and slowness of this function, and it can lead to `Max query size exceeded`
/// while using this function with generateRandom.
size_t num_values = rng() % 16 + 1;
std::vector<Int16> values(num_values);
/// Generate random numbers from range [-(max_value + 1), max_value - num_values + 1].
for (Int16 & x : values)
x = rng() % (2 * max_value + 3 - num_values) - max_value - 1;
/// Make all numbers unique.
std::sort(values.begin(), values.end());
for (size_t i = 0; i < num_values; ++i)
values[i] += i;
std::shuffle(values.begin(), values.end(), rng);
for (size_t i = 0; i != num_values; ++i)
{
if (i != 0)
writeCString(", ", buf);
writeString("'" + column_name + "V" + std::to_string(i) + "' = " + std::to_string(values[i]), buf);
}
}
void writeMapKeyType(const String & column_name, pcg64 & rng, WriteBuffer & buf)
{
TypeIndex type = map_key_types[rng() % map_key_types.size()];
switch (type)
{
case TypeIndex::FixedString:
writeString("FixedString(" + std::to_string(rng() % MAX_FIXEDSTRING_SIZE_WITHOUT_SUSPICIOUS + 1) + ")", buf);
break;
case TypeIndex::LowCardinality:
writeCString("LowCardinality(", buf);
/// Map key supports only String and FixedString inside LowCardinality.
if (rng() % 2)
writeCString("String", buf);
else
writeString("FixedString(" + std::to_string(rng() % MAX_FIXEDSTRING_SIZE_WITHOUT_SUSPICIOUS + 1) + ")", buf);
writeChar(')', buf);
break;
case TypeIndex::Enum8:
writeCString("Enum8(", buf);
writeEnumValues(column_name, rng, buf, INT8_MAX);
writeChar(')', buf);
break;
case TypeIndex::Enum16:
writeCString("Enum16(", buf);
writeEnumValues(column_name, rng, buf, INT16_MAX);
writeChar(')', buf);
break;
default:
writeString(magic_enum::enum_name<TypeIndex>(type), buf);
break;
}
}
template <bool allow_complex_types = true>
void writeRandomType(const String & column_name, pcg64 & rng, WriteBuffer & buf, bool allow_suspicious_lc_types, size_t depth = 0)
{
if (allow_complex_types && depth > MAX_DEPTH)
writeRandomType<false>(column_name, rng, buf, depth);
constexpr auto all_types = getAllTypes<allow_complex_types>();
auto type = all_types[rng() % all_types.size()];
switch (type)
{
case TypeIndex::UInt8:
if (rng() % 2)
writeCString("UInt8", buf);
else
writeCString("Bool", buf);
return;
case TypeIndex::FixedString:
writeString("FixedString(" + std::to_string(rng() % MAX_FIXEDSTRING_SIZE_WITHOUT_SUSPICIOUS + 1) + ")", buf);
return;
case TypeIndex::DateTime64:
writeString("DateTime64(" + std::to_string(rng() % MAX_DATETIME64_PRECISION + 1) + ")", buf);
return;
case TypeIndex::Decimal32:
writeString("Decimal32(" + std::to_string(rng() % MAX_DECIMAL32_PRECISION + 1) + ")", buf);
return;
case TypeIndex::Decimal64:
writeString("Decimal64(" + std::to_string(rng() % MAX_DECIMAL64_PRECISION + 1) + ")", buf);
return;
case TypeIndex::Decimal128:
writeString("Decimal128(" + std::to_string(rng() % MAX_DECIMAL128_PRECISION + 1) + ")", buf);
return;
case TypeIndex::Decimal256:
writeString("Decimal256(" + std::to_string(rng() % MAX_DECIMAL256_PRECISION + 1) + ")", buf);
return;
case TypeIndex::Enum8:
writeCString("Enum8(", buf);
writeEnumValues(column_name, rng, buf, INT8_MAX);
writeChar(')', buf);
return;
case TypeIndex::Enum16:
writeCString("Enum16(", buf);
writeEnumValues(column_name, rng, buf, INT16_MAX);
writeChar(')', buf);
return;
case TypeIndex::LowCardinality:
writeCString("LowCardinality(", buf);
writeLowCardinalityNestedType(rng, buf, allow_suspicious_lc_types);
writeChar(')', buf);
return;
case TypeIndex::Nullable:
{
writeCString("Nullable(", buf);
writeRandomType<false>(column_name, rng, buf, allow_suspicious_lc_types, depth + 1);
writeChar(')', buf);
return;
}
case TypeIndex::Array:
{
writeCString("Array(", buf);
writeRandomType(column_name, rng, buf, allow_suspicious_lc_types, depth + 1);
writeChar(')', buf);
return;
}
case TypeIndex::Map:
{
writeCString("Map(", buf);
writeMapKeyType(column_name, rng, buf);
writeCString(", ", buf);
writeRandomType(column_name, rng, buf, allow_suspicious_lc_types, depth + 1);
writeChar(')', buf);
return;
}
case TypeIndex::Tuple:
{
size_t elements = rng() % MAX_TUPLE_ELEMENTS + 1;
bool generate_nested = rng() % 2;
bool generate_named_tuple = rng() % 2;
if (generate_nested)
writeCString("Nested(", buf);
else
writeCString("Tuple(", buf);
for (size_t i = 0; i != elements; ++i)
{
if (i != 0)
writeCString(", ", buf);
String element_name = "e" + std::to_string(i + 1);
if (generate_named_tuple || generate_nested)
{
writeString(element_name, buf);
writeChar(' ', buf);
}
writeRandomType(element_name, rng, buf, allow_suspicious_lc_types, depth + 1);
}
writeChar(')', buf);
return;
}
default:
writeString(magic_enum::enum_name<TypeIndex>(type), buf);
return;
}
}
void writeRandomStructure(pcg64 & rng, size_t number_of_columns, WriteBuffer & buf, bool allow_suspicious_lc_types)
{
for (size_t i = 0; i != number_of_columns; ++i)
{
if (i != 0)
writeCString(", ", buf);
String column_name = "c" + std::to_string(i + 1);
writeString(column_name, buf);
writeChar(' ', buf);
writeRandomType(column_name, rng, buf, allow_suspicious_lc_types);
}
}
}
DataTypePtr FunctionGenerateRandomStructure::getReturnTypeImpl(const DataTypes & arguments) const
{
if (arguments.size() > 2)
throw Exception(
ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH,
"Number of arguments for function {} doesn't match: passed {}, expected from 0 to 2",
getName(), arguments.size());
for (size_t i = 0; i != arguments.size(); ++i)
{
if (!isUInt(arguments[i]) && !arguments[i]->onlyNull())
{
throw Exception(
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Illegal type {} of the {} argument of function {}, expected unsigned integer or Null",
arguments[i]->getName(),
i + 1,
getName());
}
}
return std::make_shared<DataTypeString>();
}
ColumnPtr FunctionGenerateRandomStructure::executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const
{
size_t seed = randomSeed();
size_t number_of_columns = 0;
if (!arguments.empty() && !arguments[0].column->onlyNull())
{
number_of_columns = arguments[0].column->getUInt(0);
if (number_of_columns > MAX_NUMBER_OF_COLUMNS)
throw Exception(
ErrorCodes::BAD_ARGUMENTS,
"Maximum allowed number of columns is {}, got {}",
MAX_NUMBER_OF_COLUMNS,
number_of_columns);
}
if (arguments.size() > 1 && !arguments[1].column->onlyNull())
seed = arguments[1].column->getUInt(0);
pcg64 rng(seed);
if (number_of_columns == 0)
number_of_columns = generateNumberOfColumns(rng);
auto col_res = ColumnString::create();
auto & string_column = assert_cast<ColumnString &>(*col_res);
auto & chars = string_column.getChars();
WriteBufferFromVector buf(chars);
writeRandomStructure(rng, number_of_columns, buf, allow_suspicious_lc_types);
buf.finalize();
chars.push_back(0);
string_column.getOffsets().push_back(chars.size());
return ColumnConst::create(std::move(col_res), input_rows_count);
}
String FunctionGenerateRandomStructure::generateRandomStructure(size_t seed, const ContextPtr & context)
{
pcg64 rng(seed);
size_t number_of_columns = generateNumberOfColumns(rng);
WriteBufferFromOwnString buf;
writeRandomStructure(rng, number_of_columns, buf, context->getSettingsRef().allow_suspicious_low_cardinality_types);
return buf.str();
}
REGISTER_FUNCTION(GenerateRandomStructure)
{
factory.registerFunction<FunctionGenerateRandomStructure>(FunctionDocumentation
{
.description=R"(
Generates a random table structure.
This function takes 2 optional constant arguments:
the number of columns in the result structure (random by default) and random seed (random by default)
The maximum number of columns is 128.
The function returns a value of type String.
)",
.examples{
{"random", "SELECT generateRandomStructure()", "c1 UInt32, c2 FixedString(25)"},
{"with specified number of columns", "SELECT generateRandomStructure(3)", "c1 String, c2 Array(Int32), c3 LowCardinality(String)"},
{"with specified seed", "SELECT generateRandomStructure(1, 42)", "c1 UInt128"},
},
.categories{"Random"}
},
FunctionFactory::CaseSensitive);
}
}
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