1#include <Functions/IFunctionImpl.h>
2#include <Functions/FunctionFactory.h>
3#include <DataTypes/DataTypesNumber.h>
4#include <Columns/ColumnsNumber.h>
5#include <atomic>
6
7
8namespace DB
9{
10
11/** Incremental block number among calls of this function. */
12class FunctionBlockNumber : public IFunction
13{
14private:
15 std::atomic<size_t> block_number{0};
16
17public:
18 static constexpr auto name = "blockNumber";
19 static FunctionPtr create(const Context &)
20 {
21 return std::make_shared<FunctionBlockNumber>();
22 }
23
24 /// Get the function name.
25 String getName() const override
26 {
27 return name;
28 }
29
30 bool isStateful() const override
31 {
32 return true;
33 }
34
35 size_t getNumberOfArguments() const override
36 {
37 return 0;
38 }
39
40 bool isDeterministic() const override { return false; }
41
42 bool isDeterministicInScopeOfQuery() const override
43 {
44 return false;
45 }
46
47 DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
48 {
49 return std::make_shared<DataTypeUInt64>();
50 }
51
52 void executeImpl(Block & block, const ColumnNumbers &, size_t result, size_t input_rows_count) override
53 {
54 size_t current_block_number = block_number++;
55 block.getByPosition(result).column = ColumnUInt64::create(input_rows_count, current_block_number);
56 }
57};
58
59
60void registerFunctionBlockNumber(FunctionFactory & factory)
61{
62 factory.registerFunction<FunctionBlockNumber>();
63}
64
65}
66