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113 lines
3.3 KiB
C++
113 lines
3.3 KiB
C++
#include <iostream>
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#include <IO/WriteBufferFromOStream.h>
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#include <Storages/StorageLog.h>
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#include <Formats/FormatFactory.h>
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#include <DataStreams/LimitBlockInputStream.h>
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#include <DataStreams/IBlockOutputStream.h>
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#include <DataStreams/copyData.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <Columns/ColumnsNumber.h>
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#include <Interpreters/Context.h>
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#include <Common/typeid_cast.h>
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#include <Disks/DiskLocal.h>
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#include <Processors/Executors/TreeExecutorBlockInputStream.h>
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int main(int, char **)
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try
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{
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using namespace DB;
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const size_t rows = 10000000;
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/// create table with a pair of columns
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NamesAndTypesList names_and_types;
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names_and_types.emplace_back("a", std::make_shared<DataTypeUInt64>());
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names_and_types.emplace_back("b", std::make_shared<DataTypeUInt8>());
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auto context = Context::createGlobal();
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context.makeGlobalContext();
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context.setPath("./");
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DiskPtr disk = std::make_unique<DiskLocal>("default", "./", 0);
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StoragePtr table = StorageLog::create(disk, "table/", StorageID("test", "test"), ColumnsDescription{names_and_types}, ConstraintsDescription{}, 1048576);
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table->startup();
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/// write into it
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{
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Block block;
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{
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ColumnWithTypeAndName column;
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column.name = "a";
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column.type = table->getColumn("a").type;
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auto col = column.type->createColumn();
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ColumnUInt64::Container & vec = typeid_cast<ColumnUInt64 &>(*col).getData();
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vec.resize(rows);
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for (size_t i = 0; i < rows; ++i)
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vec[i] = i;
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column.column = std::move(col);
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block.insert(column);
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}
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{
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ColumnWithTypeAndName column;
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column.name = "b";
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column.type = table->getColumn("b").type;
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auto col = column.type->createColumn();
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ColumnUInt8::Container & vec = typeid_cast<ColumnUInt8 &>(*col).getData();
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vec.resize(rows);
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for (size_t i = 0; i < rows; ++i)
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vec[i] = i * 2;
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column.column = std::move(col);
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block.insert(column);
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}
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BlockOutputStreamPtr out = table->write({}, context);
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out->write(block);
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}
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/// read from it
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{
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Names column_names;
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column_names.push_back("a");
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column_names.push_back("b");
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QueryProcessingStage::Enum stage = table->getQueryProcessingStage(context);
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BlockInputStreamPtr in = std::make_shared<TreeExecutorBlockInputStream>(std::move(table->read(column_names, {}, context, stage, 8192, 1)[0]));
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Block sample;
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{
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ColumnWithTypeAndName col;
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col.type = std::make_shared<DataTypeUInt64>();
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sample.insert(std::move(col));
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}
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{
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ColumnWithTypeAndName col;
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col.type = std::make_shared<DataTypeUInt8>();
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sample.insert(std::move(col));
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}
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WriteBufferFromOStream out_buf(std::cout);
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LimitBlockInputStream in_limit(in, 10, 0);
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BlockOutputStreamPtr output = FormatFactory::instance().getOutput("TabSeparated", out_buf, sample, context);
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copyData(in_limit, *output);
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}
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return 0;
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}
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catch (const DB::Exception & e)
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{
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std::cerr << e.what() << ", " << e.displayText() << std::endl;
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return 1;
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}
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