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121 lines
3.2 KiB
C++
121 lines
3.2 KiB
C++
#include <DB/DataStreams/AggregatingSortedBlockInputStream.h>
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namespace DB
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{
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void AggregatingSortedBlockInputStream::insertCurrentRow(ColumnPlainPtrs & merged_columns)
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{
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for (size_t i = 0; i < num_columns; ++i)
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merged_columns[i]->insert(current_row[i]);
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}
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Block AggregatingSortedBlockInputStream::readImpl()
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{
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if (!children.size())
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return Block();
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if (children.size() == 1)
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return children[0]->read();
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Block merged_block;
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ColumnPlainPtrs merged_columns;
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init(merged_block, merged_columns);
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if (merged_columns.empty())
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return Block();
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/// Дополнительная инициализация.
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if (current_row.empty())
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{
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current_row.resize(num_columns);
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current_key.resize(description.size());
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next_key.resize(description.size());
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/// Заполним номера столбцов, которые нужно доагрегировать.
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for (size_t i = 0; i < num_columns; ++i)
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{
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ColumnWithNameAndType & column = merged_block.getByPosition(i);
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/// Оставляем только состояния аггрегатных функций.
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if (strncmp(column.type->getName().data(), "AggregateFunction", strlen("AggregateFunction")) != 0)
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continue;
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/// Входят ли в PK?
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SortDescription::const_iterator it = description.begin();
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for (; it != description.end(); ++it)
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if (it->column_name == column.name || (it->column_name.empty() && it->column_number == i))
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break;
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if (it != description.end())
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continue;
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column_numbers_to_aggregate.push_back(i);
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}
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}
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columns_to_aggregate.resize(column_numbers_to_aggregate.size());
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for (size_t i = 0, size = columns_to_aggregate.size(); i < size; ++i)
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columns_to_aggregate[i] = typeid_cast<ColumnAggregateFunction *>(merged_columns[column_numbers_to_aggregate[i]]);
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if (has_collation)
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merge(merged_block, merged_columns, queue_with_collation);
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else
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merge(merged_block, merged_columns, queue);
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return merged_block;
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}
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template<class TSortCursor>
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void AggregatingSortedBlockInputStream::merge(Block & merged_block, ColumnPlainPtrs & merged_columns, std::priority_queue<TSortCursor> & queue)
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{
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size_t merged_rows = 0;
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/// Вынимаем строки в нужном порядке и кладём в merged_block, пока строк не больше max_block_size
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while (!queue.empty())
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{
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TSortCursor current = queue.top();
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setPrimaryKey(next_key, current);
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/// если накопилось достаточно строк и последняя посчитана полностью
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if (next_key != current_key && merged_rows >= max_block_size)
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return;
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queue.pop();
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if (next_key != current_key)
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{
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current_key = std::move(next_key);
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next_key.resize(description.size());
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/// Запишем данные для очередной группы.
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setRow(current_row, current);
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insertCurrentRow(merged_columns);
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++merged_rows;
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}
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else
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{
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addRow(current);
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}
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if (!current->isLast())
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{
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current->next();
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queue.push(current);
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}
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else
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{
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/// Достаём из соответствующего источника следующий блок, если есть.
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fetchNextBlock(current, queue);
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}
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}
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children.clear();
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}
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}
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