1 | #include <iostream> |
2 | |
3 | #include <IO/WriteBufferFromOStream.h> |
4 | #include <Storages/StorageLog.h> |
5 | #include <Formats/FormatFactory.h> |
6 | #include <DataStreams/LimitBlockInputStream.h> |
7 | #include <DataStreams/IBlockOutputStream.h> |
8 | #include <DataStreams/copyData.h> |
9 | #include <DataTypes/DataTypesNumber.h> |
10 | #include <Columns/ColumnsNumber.h> |
11 | #include <Interpreters/Context.h> |
12 | #include <Common/typeid_cast.h> |
13 | |
14 | |
15 | int main(int, char **) |
16 | try |
17 | { |
18 | using namespace DB; |
19 | |
20 | const size_t rows = 10000000; |
21 | |
22 | /// create table with a pair of columns |
23 | |
24 | NamesAndTypesList names_and_types; |
25 | names_and_types.emplace_back("a" , std::make_shared<DataTypeUInt64>()); |
26 | names_and_types.emplace_back("b" , std::make_shared<DataTypeUInt8>()); |
27 | |
28 | auto context = Context::createGlobal(); |
29 | context.makeGlobalContext(); |
30 | context.setPath("./" ); |
31 | |
32 | StoragePtr table = StorageLog::create("./" , "test" , "test" , ColumnsDescription{names_and_types}, ConstraintsDescription{}, 1048576, context); |
33 | table->startup(); |
34 | |
35 | /// write into it |
36 | { |
37 | Block block; |
38 | |
39 | { |
40 | ColumnWithTypeAndName column; |
41 | column.name = "a" ; |
42 | column.type = table->getColumn("a" ).type; |
43 | auto col = column.type->createColumn(); |
44 | ColumnUInt64::Container & vec = typeid_cast<ColumnUInt64 &>(*col).getData(); |
45 | |
46 | vec.resize(rows); |
47 | for (size_t i = 0; i < rows; ++i) |
48 | vec[i] = i; |
49 | |
50 | column.column = std::move(col); |
51 | block.insert(column); |
52 | } |
53 | |
54 | { |
55 | ColumnWithTypeAndName column; |
56 | column.name = "b" ; |
57 | column.type = table->getColumn("b" ).type; |
58 | auto col = column.type->createColumn(); |
59 | ColumnUInt8::Container & vec = typeid_cast<ColumnUInt8 &>(*col).getData(); |
60 | |
61 | vec.resize(rows); |
62 | for (size_t i = 0; i < rows; ++i) |
63 | vec[i] = i * 2; |
64 | |
65 | column.column = std::move(col); |
66 | block.insert(column); |
67 | } |
68 | |
69 | BlockOutputStreamPtr out = table->write({}, context); |
70 | out->write(block); |
71 | } |
72 | |
73 | /// read from it |
74 | { |
75 | Names column_names; |
76 | column_names.push_back("a" ); |
77 | column_names.push_back("b" ); |
78 | |
79 | QueryProcessingStage::Enum stage = table->getQueryProcessingStage(context); |
80 | |
81 | BlockInputStreamPtr in = table->read(column_names, {}, context, stage, 8192, 1)[0]; |
82 | |
83 | Block sample; |
84 | { |
85 | ColumnWithTypeAndName col; |
86 | col.type = std::make_shared<DataTypeUInt64>(); |
87 | sample.insert(std::move(col)); |
88 | } |
89 | { |
90 | ColumnWithTypeAndName col; |
91 | col.type = std::make_shared<DataTypeUInt8>(); |
92 | sample.insert(std::move(col)); |
93 | } |
94 | |
95 | WriteBufferFromOStream out_buf(std::cout); |
96 | |
97 | LimitBlockInputStream in_limit(in, 10, 0); |
98 | BlockOutputStreamPtr output = FormatFactory::instance().getOutput("TabSeparated" , out_buf, sample, context); |
99 | |
100 | copyData(in_limit, *output); |
101 | } |
102 | |
103 | return 0; |
104 | } |
105 | catch (const DB::Exception & e) |
106 | { |
107 | std::cerr << e.what() << ", " << e.displayText() << std::endl; |
108 | return 1; |
109 | } |
110 | |