forked from ClickHouse/ClickHouse
-
Notifications
You must be signed in to change notification settings - Fork 3
Expand file tree
/
Copy pathNegativeOffsetTransform.cpp
More file actions
288 lines (225 loc) · 7.7 KB
/
Copy pathNegativeOffsetTransform.cpp
File metadata and controls
288 lines (225 loc) · 7.7 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
#include <Columns/IColumn.h>
#include <Processors/NegativeOffsetTransform.h>
#include <Processors/Port.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
NegativeOffsetTransform::NegativeOffsetTransform(const Block & header_, UInt64 offset_, size_t num_streams)
: IProcessor(InputPorts(num_streams, header_), OutputPorts(num_streams, header_))
, offset(offset_)
{
ports_data.resize(num_streams);
size_t cur_stream = 0;
for (auto & input : inputs)
{
ports_data[cur_stream].input_port = &input;
++cur_stream;
}
cur_stream = 0;
for (auto & output : outputs)
{
ports_data[cur_stream].output_port = &output;
++cur_stream;
}
}
/// First, our goal is to pull all the data from input ports. Once we have reached the end,
/// then it is clear what should be part of the `offset` and what should be pushed out to the output ports.
NegativeOffsetTransform::Status NegativeOffsetTransform::prepare()
{
if (allOutputsFinished())
{
for (auto & port : ports_data)
port.input_port->close();
return Status::Finished;
}
if (stage == Stage::Pull)
{
bool has_data_need = false;
bool has_full_port = false;
auto process = [&](size_t pos)
{
auto status = advancePort(ports_data[pos]);
switch (status)
{
case IProcessor::Status::Finished: {
if (!ports_data[pos].is_input_port_finished)
{
ports_data[pos].is_input_port_finished = true;
++num_input_ports_finished;
}
return;
}
case IProcessor::Status::NeedData: {
has_data_need = true;
return;
}
case IProcessor::Status::PortFull: {
has_full_port = true;
return;
}
default:
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"Unexpected status in NegativeOffsetTransform::advancePort : {}",
IProcessor::statusToName(status));
}
};
for (size_t pos = 0; pos < ports_data.size(); ++pos)
process(pos);
if (has_data_need)
return Status::NeedData;
if (has_full_port)
return Status::PortFull;
/// All data fetching is done. We can now start pushing out the remaining data
if (num_input_ports_finished == ports_data.size())
{
stage = Stage::Push;
}
else
{
return Status::NeedData;
}
}
if (stage == Stage::Push)
{
Status status = tryPushWholeFrontChunk();
if (status != Status::Finished)
return status;
status = tryPushRemainingChunkPrefix();
if (status != Status::Finished)
return status;
if (queued_row_count > offset)
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"In NegativeOffsetTransform::prepare, at this point queued rows {} should be less than or equal to offset {}",
queued_row_count,
offset);
for (auto & port : ports_data)
{
port.input_port->close();
port.output_port->finish();
}
return Status::Finished;
}
throw Exception(ErrorCodes::LOGICAL_ERROR, "NegativeOffsetTransform::prepare in unknown stage");
}
NegativeOffsetTransform::Status NegativeOffsetTransform::advancePort(PortsData & data)
{
auto & input = *data.input_port;
/// Check can input.
if (input.isFinished())
{
return Status::Finished;
}
/// If we already have enough rows buffered, try to push whole chunks when output ports become available.
Status push_status = tryPushWholeFrontChunk();
if (push_status != Status::Finished)
return push_status;
input.setNeeded();
if (input.hasData())
{
Chunk chunk = input.pull(true);
input.setNeeded();
auto rows = chunk.getNumRows();
queued_row_count += rows;
if (rows_before_limit_at_least)
{
rows_before_limit_at_least->add(rows);
}
queue.push(ChunkWithPort{std::move(chunk)});
/// Push whole chunks while we can still keep the required offset.
/// Ensures that queue does not grow too large.
push_status = tryPushWholeFrontChunk();
if (push_status != Status::Finished)
return push_status;
}
if (input.isFinished())
return Status::Finished;
return Status::NeedData;
}
IProcessor::Status NegativeOffsetTransform::tryPushWholeFrontChunk()
{
/// Need to keep at least 'offset' rows queued.
while (queued_row_count > offset)
{
chassert(!queue.empty() && "Queue is empty in tryPushWholeFrontChunk");
auto & front = queue.front();
Chunk & chunk = front.chunk;
const UInt64 front_chunk_rows = chunk.getNumRows();
/// Make sure that front chunk can be completey pushed without potentially
/// going into the offset area.
if (queued_row_count - front_chunk_rows < offset)
return Status::Finished;
auto * output = getAvailableOutputPort();
if (!output)
return Status::PortFull;
output->push(std::move(chunk));
queue.pop();
queued_row_count -= front_chunk_rows;
}
return Status::Finished;
}
IProcessor::Status NegativeOffsetTransform::tryPushRemainingChunkPrefix()
{
/// Need to keep at least 'offset' rows queued.
if (queued_row_count <= offset)
return Status::Finished;
auto & front = queue.front();
Chunk & chunk = front.chunk;
const UInt64 front_chunk_rows = chunk.getNumRows();
if (queued_row_count - front_chunk_rows >= offset)
throw Exception(
ErrorCodes::LOGICAL_ERROR,
"NegativeOffsetTransformtryPushRemainingChunkPrefix must not be required to fully push the front chunk");
auto * output = getAvailableOutputPort();
if (!output)
return Status::PortFull;
/// queued_row_count <---------------------->
/// front_chunk_rows <---------->
/// offset <--------------->
/// <-----> (cut `take` amount)
/// Push the prefix that leaves exactly 'offset' queued.
const UInt64 take = queued_row_count - offset;
const UInt64 num_columns = chunk.getNumColumns();
auto columns = chunk.detachColumns();
for (UInt64 i = 0; i < num_columns; ++i)
columns[i] = columns[i]->cut(0, take);
chunk.setColumns(std::move(columns), take);
/// Remove the remaining rows after the cut.
queued_row_count -= (front_chunk_rows - take);
output->push(std::move(chunk));
queue.pop();
queued_row_count -= take;
return Status::Finished;
}
bool NegativeOffsetTransform::allOutputsFinished() const
{
for (const auto & data : ports_data)
{
if (!data.output_port->isFinished())
return false;
}
return true;
}
OutputPort * NegativeOffsetTransform::getAvailableOutputPort()
{
const size_t num_outputs = ports_data.size();
if (num_outputs == 0)
return nullptr;
for (size_t i = 0; i < num_outputs; ++i)
{
const size_t idx = (next_output_port + i) % num_outputs;
auto & output = *ports_data[idx].output_port;
if (output.isFinished())
continue;
if (!output.canPush())
continue;
next_output_port = (idx + 1) % num_outputs;
return &output;
}
return nullptr;
}
}