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63 lines
2.4 KiB
C++
63 lines
2.4 KiB
C++
#include <TableFunctions/ITableFunction.h>
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#include <TableFunctions/TableFunctionNumbers.h>
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#include <TableFunctions/TableFunctionFactory.h>
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#include <Parsers/ASTFunction.h>
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#include <Parsers/ASTLiteral.h>
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#include <Common/typeid_cast.h>
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#include <Storages/System/StorageSystemNumbers.h>
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#include <Interpreters/evaluateConstantExpression.h>
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#include <Interpreters/Context.h>
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#include <DataTypes/DataTypesNumber.h>
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#include "registerTableFunctions.h"
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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}
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template <bool multithreaded>
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ColumnsDescription TableFunctionNumbers<multithreaded>::getActualTableStructure(const Context & /*context*/) const
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{
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/// NOTE: https://bugs.llvm.org/show_bug.cgi?id=47418
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return ColumnsDescription{{{"number", std::make_shared<DataTypeUInt64>()}}};
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}
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template <bool multithreaded>
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StoragePtr TableFunctionNumbers<multithreaded>::executeImpl(const ASTPtr & ast_function, const Context & context, const std::string & table_name, ColumnsDescription /*cached_columns*/) const
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{
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if (const auto * function = ast_function->as<ASTFunction>())
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{
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auto arguments = function->arguments->children;
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if (arguments.size() != 1 && arguments.size() != 2)
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throw Exception("Table function '" + getName() + "' requires 'length' or 'offset, length'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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UInt64 offset = arguments.size() == 2 ? evaluateArgument(context, arguments[0]) : 0;
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UInt64 length = arguments.size() == 2 ? evaluateArgument(context, arguments[1]) : evaluateArgument(context, arguments[0]);
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auto res = StorageSystemNumbers::create(StorageID(getDatabaseName(), table_name), multithreaded, length, offset, false);
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res->startup();
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return res;
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}
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throw Exception("Table function '" + getName() + "' requires 'limit' or 'offset, limit'.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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}
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void registerTableFunctionNumbers(TableFunctionFactory & factory)
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{
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factory.registerFunction<TableFunctionNumbers<true>>();
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factory.registerFunction<TableFunctionNumbers<false>>();
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}
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template <bool multithreaded>
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UInt64 TableFunctionNumbers<multithreaded>::evaluateArgument(const Context & context, ASTPtr & argument) const
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{
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return evaluateConstantExpressionOrIdentifierAsLiteral(argument, context)->as<ASTLiteral &>().value.safeGet<UInt64>();
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}
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}
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