1 | #pragma once |
---|---|
2 | |
3 | #include <Core/SortDescription.h> |
4 | #include <Interpreters/sortBlock.h> |
5 | #include <DataStreams/IBlockInputStream.h> |
6 | |
7 | |
8 | namespace DB |
9 | { |
10 | |
11 | /** Takes stream already sorted by `x` and finishes sorting it by (`x`, `y`). |
12 | * During sorting only blocks with rows that equal by `x` saved in RAM. |
13 | * */ |
14 | class FinishSortingBlockInputStream : public IBlockInputStream |
15 | { |
16 | public: |
17 | /// limit - if not 0, allowed to return just first 'limit' rows in sorted order. |
18 | FinishSortingBlockInputStream(const BlockInputStreamPtr & input, const SortDescription & description_sorted_, |
19 | const SortDescription & description_to_sort_, |
20 | size_t max_merged_block_size_, UInt64 limit_); |
21 | |
22 | String getName() const override { return "FinishSorting"; } |
23 | |
24 | bool isSortedOutput() const override { return true; } |
25 | const SortDescription & getSortDescription() const override { return description_to_sort; } |
26 | |
27 | Block getHeader() const override { return header; } |
28 | |
29 | protected: |
30 | Block readImpl() override; |
31 | |
32 | private: |
33 | SortDescription description_sorted; |
34 | SortDescription description_to_sort; |
35 | size_t max_merged_block_size; |
36 | UInt64 limit; |
37 | |
38 | Block tail_block; |
39 | Blocks blocks; |
40 | |
41 | std::unique_ptr<IBlockInputStream> impl; |
42 | |
43 | /// Before operation, will remove constant columns from blocks. And after, place constant columns back. |
44 | /// to avoid excessive virtual function calls |
45 | /// Save original block structure here. |
46 | Block header; |
47 | |
48 | bool end_of_stream = false; |
49 | size_t total_rows_processed = 0; |
50 | }; |
51 | } |
52 |