ClickHouse/dbms/src/DataStreams/SummingSortedBlockInputStream.cpp

490 lines
16 KiB
C++

#include <DataStreams/SummingSortedBlockInputStream.h>
#include <DataTypes/DataTypesNumber.h>
#include <DataTypes/NestedUtils.h>
#include <DataTypes/DataTypeTuple.h>
#include <DataTypes/DataTypeArray.h>
#include <Columns/ColumnTuple.h>
#include <Common/StringUtils/StringUtils.h>
#include <Common/FieldVisitors.h>
#include <common/logger_useful.h>
#include <Common/typeid_cast.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <Interpreters/Context.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
}
namespace
{
bool isInPrimaryKey(const SortDescription & description, const std::string & name, const size_t number)
{
for (auto & desc : description)
if (desc.column_name == name || (desc.column_name.empty() && desc.column_number == number))
return true;
return false;
}
}
SummingSortedBlockInputStream::SummingSortedBlockInputStream(
const BlockInputStreams & inputs_,
const SortDescription & description_,
/// List of columns to be summed. If empty, all numeric columns that are not in the description are taken.
const Names & column_names_to_sum,
size_t max_block_size_)
: MergingSortedBlockInputStream(inputs_, description_, max_block_size_)
{
current_row.resize(num_columns);
/// name of nested structure -> the column numbers that refer to it.
std::unordered_map<std::string, std::vector<size_t>> discovered_maps;
/** Fill in the column numbers, which must be summed.
* This can only be numeric columns that are not part of the sort key.
* If a non-empty column_names_to_sum is specified, then we only take these columns.
* Some columns from column_names_to_sum may not be found. This is ignored.
*/
for (size_t i = 0; i < num_columns; ++i)
{
const ColumnWithTypeAndName & column = header.safeGetByPosition(i);
/// Discover nested Maps and find columns for summation
if (typeid_cast<const DataTypeArray *>(column.type.get()))
{
const auto map_name = Nested::extractTableName(column.name);
/// if nested table name ends with `Map` it is a possible candidate for special handling
if (map_name == column.name || !endsWith(map_name, "Map"))
{
column_numbers_not_to_aggregate.push_back(i);
continue;
}
discovered_maps[map_name].emplace_back(i);
}
else
{
if (!column.type->isSummable())
{
column_numbers_not_to_aggregate.push_back(i);
continue;
}
/// Are they inside the PK?
if (isInPrimaryKey(description, column.name, i))
{
column_numbers_not_to_aggregate.push_back(i);
continue;
}
if (column_names_to_sum.empty()
|| column_names_to_sum.end() !=
std::find(column_names_to_sum.begin(), column_names_to_sum.end(), column.name))
{
// Create aggregator to sum this column
AggregateDescription desc;
desc.column_numbers = {i};
desc.init("sumWithOverflow", {column.type});
columns_to_aggregate.emplace_back(std::move(desc));
}
else
{
// Column is not going to be summed, use last value
column_numbers_not_to_aggregate.push_back(i);
}
}
}
/// select actual nested Maps from list of candidates
for (const auto & map : discovered_maps)
{
/// map should contain at least two elements (key -> value)
if (map.second.size() < 2)
{
for (auto col : map.second)
column_numbers_not_to_aggregate.push_back(col);
continue;
}
/// no elements of map could be in primary key
auto column_num_it = map.second.begin();
for (; column_num_it != map.second.end(); ++column_num_it)
if (isInPrimaryKey(description, header.safeGetByPosition(*column_num_it).name, *column_num_it))
break;
if (column_num_it != map.second.end())
{
for (auto col : map.second)
column_numbers_not_to_aggregate.push_back(col);
continue;
}
DataTypes argument_types;
AggregateDescription desc;
MapDescription map_desc;
column_num_it = map.second.begin();
for (; column_num_it != map.second.end(); ++column_num_it)
{
const ColumnWithTypeAndName & key_col = header.safeGetByPosition(*column_num_it);
const String & name = key_col.name;
const IDataType & nested_type = *static_cast<const DataTypeArray *>(key_col.type.get())->getNestedType();
if (column_num_it == map.second.begin()
|| endsWith(name, "ID")
|| endsWith(name, "Key")
|| endsWith(name, "Type"))
{
if (!nested_type.isValueRepresentedByInteger())
break;
map_desc.key_col_nums.push_back(*column_num_it);
}
else
{
if (!nested_type.isSummable())
break;
map_desc.val_col_nums.push_back(*column_num_it);
}
// Add column to function arguments
desc.column_numbers.push_back(*column_num_it);
argument_types.push_back(key_col.type);
}
if (column_num_it != map.second.end())
{
for (auto col : map.second)
column_numbers_not_to_aggregate.push_back(col);
continue;
}
if (map_desc.key_col_nums.size() == 1)
{
// Create summation for all value columns in the map
desc.init("sumMap", argument_types);
columns_to_aggregate.emplace_back(std::move(desc));
}
else
{
// Fall back to legacy mergeMaps for composite keys
for (auto col : map.second)
column_numbers_not_to_aggregate.push_back(col);
maps_to_sum.emplace_back(std::move(map_desc));
}
}
}
void SummingSortedBlockInputStream::insertCurrentRowIfNeeded(MutableColumns & merged_columns, bool force_insertion)
{
for (auto & desc : columns_to_aggregate)
{
// Do not insert if the aggregation state hasn't been created
if (desc.created)
{
try
{
desc.function->insertResultInto(desc.state.data(), *desc.merged_column);
/// Update zero status of current row
if (desc.column_numbers.size() == 1)
{
// Flag row as non-empty if at least one column number if non-zero
current_row_is_zero = current_row_is_zero && desc.merged_column->get64(desc.merged_column->size() - 1) == 0;
}
else
{
/// It is sumMap aggregate function.
/// Assume that the row isn't empty in this case (just because it is compatible with previous version)
current_row_is_zero = false;
}
}
catch (...)
{
desc.destroyState();
throw;
}
desc.destroyState();
}
else
desc.merged_column->insertDefault();
}
/// If it is "zero" row and it is not the last row of the result block, then
/// rollback the insertion (at this moment we need rollback only cols from columns_to_aggregate)
if (!force_insertion && current_row_is_zero)
{
for (auto & desc : columns_to_aggregate)
desc.merged_column->popBack(1);
return;
}
for (auto i : column_numbers_not_to_aggregate)
merged_columns[i]->insert(current_row[i]);
/// Update per-block and per-group flags
++merged_rows;
output_is_non_empty = true;
}
Block SummingSortedBlockInputStream::readImpl()
{
if (finished)
return Block();
MutableColumns merged_columns;
init(merged_columns);
if (has_collation)
throw Exception("Logical error: " + getName() + " does not support collations", ErrorCodes::LOGICAL_ERROR);
if (merged_columns.empty())
return {};
/// Update aggregation result columns for current block
for (auto & desc : columns_to_aggregate)
{
// Wrap aggregated columns in a tuple to match function signature
if (checkDataType<DataTypeTuple>(desc.function->getReturnType().get()))
{
size_t tuple_size = desc.column_numbers.size();
MutableColumns tuple_columns(tuple_size);
for (size_t i = 0; i < tuple_size; ++i)
tuple_columns[i] = header.safeGetByPosition(desc.column_numbers[i]).column->assumeMutable();
desc.merged_column = ColumnTuple::create(std::move(tuple_columns));
}
else
desc.merged_column = header.safeGetByPosition(desc.column_numbers[0]).column->cloneEmpty();
}
merge(merged_columns, queue);
Block res = header.cloneWithColumns(std::move(merged_columns));
/// Place aggregation results into block.
for (auto & desc : columns_to_aggregate)
{
if (checkDataType<DataTypeTuple>(desc.function->getReturnType().get()))
{
/// Unpack tuple into block.
size_t tuple_size = desc.column_numbers.size();
for (size_t i = 0; i < tuple_size; ++i)
res.getByPosition(desc.column_numbers[i]).column = static_cast<const ColumnTuple &>(*desc.merged_column).getColumnPtr(i);
}
else
res.getByPosition(desc.column_numbers[0]).column = std::move(desc.merged_column);
}
return res;
}
void SummingSortedBlockInputStream::merge(MutableColumns & merged_columns, std::priority_queue<SortCursor> & queue)
{
merged_rows = 0;
/// Take the rows in needed order and put them in `merged_columns` until rows no more than `max_block_size`
while (!queue.empty())
{
SortCursor current = queue.top();
setPrimaryKeyRef(next_key, current);
bool key_differs;
if (current_key.empty()) /// The first key encountered.
{
setPrimaryKeyRef(current_key, current);
key_differs = true;
}
else
key_differs = next_key != current_key;
/// if there are enough rows and the last one is calculated completely
if (key_differs && merged_rows >= max_block_size)
return;
queue.pop();
if (key_differs)
{
/// Write the data for the previous group.
insertCurrentRowIfNeeded(merged_columns, false);
current_key.swap(next_key);
setRow(current_row, current);
/// Reset aggregation states for next row
for (auto & desc : columns_to_aggregate)
desc.createState();
// Start aggregations with current row
addRow(current);
if (maps_to_sum.empty())
{
/// We have only columns_to_aggregate. The status of current row will be determined
/// in 'insertCurrentRowIfNeeded' method on the values of aggregate functions.
current_row_is_zero = true;
}
else
{
/// We have complex maps that will be summed with 'mergeMap' method.
/// The single row is considered non zero, and the status after merging with other rows
/// will be determined in the branch below (when key_differs == false).
current_row_is_zero = false;
}
}
else
{
addRow(current);
// Merge maps only for same rows
for (const auto & desc : maps_to_sum)
if (mergeMap(desc, current_row, current))
current_row_is_zero = false;
}
if (!current->isLast())
{
current->next();
queue.push(current);
}
else
{
/// We get the next block from the corresponding source, if there is one.
fetchNextBlock(current, queue);
}
}
/// We will write the data for the last group, if it is non-zero.
/// If it is zero, and without it the output stream will be empty, we will write it anyway.
insertCurrentRowIfNeeded(merged_columns, !output_is_non_empty);
finished = true;
}
bool SummingSortedBlockInputStream::mergeMap(const MapDescription & desc, Row & row, SortCursor & cursor)
{
/// Strongly non-optimal.
Row & left = row;
Row right(left.size());
for (size_t col_num : desc.key_col_nums)
right[col_num] = (*cursor->all_columns[col_num])[cursor->pos].template get<Array>();
for (size_t col_num : desc.val_col_nums)
right[col_num] = (*cursor->all_columns[col_num])[cursor->pos].template get<Array>();
auto at_ith_column_jth_row = [&](const Row & matrix, size_t i, size_t j) -> const Field &
{
return matrix[i].get<Array>()[j];
};
auto tuple_of_nth_columns_at_jth_row = [&](const Row & matrix, const ColumnNumbers & col_nums, size_t j) -> Array
{
size_t size = col_nums.size();
Array res(size);
for (size_t col_num_index = 0; col_num_index < size; ++col_num_index)
res[col_num_index] = at_ith_column_jth_row(matrix, col_nums[col_num_index], j);
return res;
};
std::map<Array, Array> merged;
auto accumulate = [](Array & dst, const Array & src)
{
bool has_non_zero = false;
size_t size = dst.size();
for (size_t i = 0; i < size; ++i)
if (applyVisitor(FieldVisitorSum(src[i]), dst[i]))
has_non_zero = true;
return has_non_zero;
};
auto merge = [&](const Row & matrix)
{
size_t rows = matrix[desc.key_col_nums[0]].get<Array>().size();
for (size_t j = 0; j < rows; ++j)
{
Array key = tuple_of_nth_columns_at_jth_row(matrix, desc.key_col_nums, j);
Array value = tuple_of_nth_columns_at_jth_row(matrix, desc.val_col_nums, j);
auto it = merged.find(key);
if (merged.end() == it)
merged.emplace(std::move(key), std::move(value));
else
{
if (!accumulate(it->second, value))
merged.erase(it);
}
}
};
merge(left);
merge(right);
for (size_t col_num : desc.key_col_nums)
row[col_num] = Array(merged.size());
for (size_t col_num : desc.val_col_nums)
row[col_num] = Array(merged.size());
size_t row_num = 0;
for (const auto & key_value : merged)
{
for (size_t col_num_index = 0, size = desc.key_col_nums.size(); col_num_index < size; ++col_num_index)
row[desc.key_col_nums[col_num_index]].get<Array>()[row_num] = key_value.first[col_num_index];
for (size_t col_num_index = 0, size = desc.val_col_nums.size(); col_num_index < size; ++col_num_index)
row[desc.val_col_nums[col_num_index]].get<Array>()[row_num] = key_value.second[col_num_index];
++row_num;
}
return row_num != 0;
}
void SummingSortedBlockInputStream::addRow(SortCursor & cursor)
{
for (auto & desc : columns_to_aggregate)
{
if (!desc.created)
throw Exception("Logical error in SummingSortedBlockInputStream, there are no description", ErrorCodes::LOGICAL_ERROR);
// Specialized case for unary functions
if (desc.column_numbers.size() == 1)
{
auto & col = cursor->all_columns[desc.column_numbers[0]];
desc.add_function(desc.function.get(), desc.state.data(), &col, cursor->pos, nullptr);
}
else
{
// Gather all source columns into a vector
ColumnRawPtrs columns(desc.column_numbers.size());
for (size_t i = 0; i < desc.column_numbers.size(); ++i)
columns[i] = cursor->all_columns[desc.column_numbers[i]];
desc.add_function(desc.function.get(), desc.state.data(), columns.data(), cursor->pos, nullptr);
}
}
}
}