ClickHouse/src/Processors/Merges/SummingSortedTransform.cpp
2020-04-04 19:02:17 +03:00

627 lines
22 KiB
C++

#include <Processors/Merges/SummingSortedTransform.h>
#include <DataTypes/DataTypeArray.h>
#include <DataTypes/NestedUtils.h>
#include <Columns/ColumnAggregateFunction.h>
#include <Columns/ColumnTuple.h>
#include <Common/StringUtils/StringUtils.h>
#include <Common/FieldVisitors.h>
#include <Core/Row.h>
#include <IO/WriteHelpers.h>
namespace DB
{
namespace ErrorCodes
{
extern const int LOGICAL_ERROR;
extern const int CORRUPTED_DATA;
}
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;
}
/// Returns true if merge result is not empty
bool mergeMap(const SummingSortedTransform::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;
}
SummingSortedTransform::ColumnsDefinition defineColumns(
const Block & header,
const SortDescription & description,
const Names & column_names_to_sum)
{
size_t num_columns = header.columns();
SummingSortedTransform::ColumnsDefinition def;
/// 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"))
{
def.column_numbers_not_to_aggregate.push_back(i);
continue;
}
discovered_maps[map_name].emplace_back(i);
}
else
{
bool is_agg_func = WhichDataType(column.type).isAggregateFunction();
/// There are special const columns for example after prewhere sections.
if ((!column.type->isSummable() && !is_agg_func) || isColumnConst(*column.column))
{
def.column_numbers_not_to_aggregate.push_back(i);
continue;
}
/// Are they inside the PK?
if (isInPrimaryKey(description, column.name, i))
{
def.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
SummingSortedTransform::AggregateDescription desc;
desc.is_agg_func_type = is_agg_func;
desc.column_numbers = {i};
if (!is_agg_func)
{
desc.init("sumWithOverflow", {column.type});
}
def.columns_to_aggregate.emplace_back(std::move(desc));
}
else
{
// Column is not going to be summed, use last value
def.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)
def.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)
def.column_numbers_not_to_aggregate.push_back(col);
continue;
}
DataTypes argument_types;
SummingSortedTransform::AggregateDescription desc;
SummingSortedTransform::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 = *assert_cast<const DataTypeArray &>(*key_col.type).getNestedType();
if (column_num_it == map.second.begin()
|| endsWith(name, "ID")
|| endsWith(name, "Key")
|| endsWith(name, "Type"))
{
if (!nested_type.isValueRepresentedByInteger() && !isStringOrFixedString(nested_type))
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)
def.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("sumMapWithOverflow", argument_types);
def.columns_to_aggregate.emplace_back(std::move(desc));
}
else
{
// Fall back to legacy mergeMaps for composite keys
for (auto col : map.second)
def.column_numbers_not_to_aggregate.push_back(col);
def.maps_to_sum.emplace_back(std::move(map_desc));
}
}
return def;
}
MutableColumns getMergedDataColumns(
const Block & header,
const SummingSortedTransform::ColumnsDefinition & columns_definition)
{
MutableColumns columns;
columns.reserve(columns_definition.getNumColumns());
for (auto & desc : columns_definition.columns_to_aggregate)
{
// Wrap aggregated columns in a tuple to match function signature
if (!desc.is_agg_func_type && isTuple(desc.function->getReturnType()))
{
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->cloneEmpty();
columns.emplace_back(ColumnTuple::create(std::move(tuple_columns)));
}
else
columns.emplace_back(header.safeGetByPosition(desc.column_numbers[0]).column->cloneEmpty());
}
for (auto & column_number : columns_definition.column_numbers_not_to_aggregate)
columns.emplace_back(header.safeGetByPosition(column_number).type->createColumn());
return columns;
}
void finalizeChunk(
Chunk & chunk, size_t num_result_columns,
const SummingSortedTransform::ColumnsDefinition & columns_definition)
{
size_t num_rows = chunk.getNumRows();
auto columns = chunk.detachColumns();
Columns res_columns(num_result_columns);
size_t next_column = 0;
for (auto & desc : columns_definition.columns_to_aggregate)
{
auto column = std::move(columns[next_column]);
++next_column;
if (!desc.is_agg_func_type && isTuple(desc.function->getReturnType()))
{
/// Unpack tuple into block.
size_t tuple_size = desc.column_numbers.size();
for (size_t i = 0; i < tuple_size; ++i)
res_columns[desc.column_numbers[i]] = assert_cast<const ColumnTuple &>(*column).getColumnPtr(i);
}
else
res_columns[desc.column_numbers[0]] = std::move(column);
}
for (auto column_number : columns_definition.column_numbers_not_to_aggregate)
{
auto column = std::move(columns[next_column]);
++next_column;
res_columns[column_number] = std::move(column);
}
chunk.setColumns(std::move(res_columns), num_rows);
}
void setRow(Row & row, SortCursor & cursor, const Block & header)
{
size_t num_columns = row.size();
for (size_t i = 0; i < num_columns; ++i)
{
try
{
cursor->all_columns[i]->get(cursor->pos, row[i]);
}
catch (...)
{
tryLogCurrentException(__PRETTY_FUNCTION__);
/// Find out the name of the column and throw more informative exception.
String column_name;
if (i < header.columns())
{
column_name = header.safeGetByPosition(i).name;
break;
}
throw Exception("MergingSortedBlockInputStream failed to read row " + toString(cursor->pos)
+ " of column " + toString(i) + (column_name.empty() ? "" : " (" + column_name + ")"),
ErrorCodes::CORRUPTED_DATA);
}
}
}
}
SummingSortedTransform::SummingSortedTransform(
const Block & header, size_t num_inputs,
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)
: IMergingTransform(num_inputs, header, header, true)
, columns_definition(defineColumns(header, description_, column_names_to_sum))
, merged_data(getMergedDataColumns(header, columns_definition), false, max_block_size)
, description(std::move(description_))
, source_chunks(num_inputs)
, cursors(num_inputs)
{
current_row.resize(header.columns());
merged_data.initAggregateDescription(columns_definition.columns_to_aggregate);
}
void SummingSortedTransform::initializeInputs()
{
queue = SortingHeap<SortCursor>(cursors);
is_queue_initialized = true;
}
void SummingSortedTransform::consume(Chunk chunk, size_t input_number)
{
updateCursor(std::move(chunk), input_number);
if (is_queue_initialized)
queue.push(cursors[input_number]);
}
void SummingSortedTransform::updateCursor(Chunk chunk, size_t source_num)
{
auto num_rows = chunk.getNumRows();
auto columns = chunk.detachColumns();
for (auto & column : columns)
column = column->convertToFullColumnIfConst();
chunk.setColumns(std::move(columns), num_rows);
auto & source_chunk = source_chunks[source_num];
if (source_chunk)
{
/// Extend lifetime of last chunk.
last_chunk = std::move(source_chunk);
last_chunk_sort_columns = std::move(cursors[source_num].sort_columns);
source_chunk = std::move(chunk);
cursors[source_num].reset(source_chunk.getColumns(), {});
}
else
{
if (cursors[source_num].has_collation)
throw Exception("Logical error: " + getName() + " does not support collations", ErrorCodes::LOGICAL_ERROR);
source_chunk = std::move(chunk);
cursors[source_num] = SortCursorImpl(source_chunk.getColumns(), description, source_num);
}
}
void SummingSortedTransform::work()
{
merge();
prepareOutputChunk(merged_data);
if (has_output_chunk)
{
finalizeChunk(output_chunk, getOutputs().back().getHeader().columns(), columns_definition);
merged_data.initAggregateDescription(columns_definition.columns_to_aggregate);
}
}
void SummingSortedTransform::insertCurrentRowIfNeeded()
{
/// We have nothing to aggregate. It means that it could be non-zero, because we have columns_not_to_aggregate.
if (columns_definition.columns_to_aggregate.empty())
current_row_is_zero = false;
for (auto & desc : columns_definition.columns_to_aggregate)
{
// Do not insert if the aggregation state hasn't been created
if (desc.created)
{
if (desc.is_agg_func_type)
{
current_row_is_zero = false;
}
else
{
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->isDefaultAt(desc.merged_column->size() - 1);
}
else
{
/// It is sumMapWithOverflow 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, then rollback the insertion
/// (at this moment we need rollback only cols from columns_to_aggregate)
if (current_row_is_zero)
{
for (auto & desc : columns_definition.columns_to_aggregate)
desc.merged_column->popBack(1);
return;
}
merged_data.insertRow(current_row, columns_definition.column_numbers_not_to_aggregate);
}
void SummingSortedTransform::addRow(SortCursor & cursor)
{
for (auto & desc : columns_definition.columns_to_aggregate)
{
if (!desc.created)
throw Exception("Logical error in SummingSortedBlockInputStream, there are no description", ErrorCodes::LOGICAL_ERROR);
if (desc.is_agg_func_type)
{
// desc.state is not used for AggregateFunction types
auto & col = cursor->all_columns[desc.column_numbers[0]];
assert_cast<ColumnAggregateFunction &>(*desc.merged_column).insertMergeFrom(*col, cursor->pos);
}
else
{
// 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);
}
}
}
}
void SummingSortedTransform::merge()
{
/// Take the rows in needed order and put them in `merged_columns` until rows no more than `max_block_size`
while (queue.isValid())
{
bool key_differs;
bool has_previous_group = !last_key.empty();
SortCursor current = queue.current();
{
detail::RowRef current_key;
current_key.set(current);
if (!has_previous_group) /// The first key encountered.
{
key_differs = true;
current_row_is_zero = true;
}
else
key_differs = !last_key.hasEqualSortColumnsWith(current_key);
last_key = current_key;
last_chunk_sort_columns.clear();
}
if (key_differs)
{
if (has_previous_group)
/// Write the data for the previous group.
insertCurrentRowIfNeeded();
if (merged_data.hasEnoughRows())
{
/// The block is now full and the last row is calculated completely.
last_key.reset();
return;
}
setRow(current_row, current, getInputs().front().getHeader());
/// Reset aggregation states for next row
for (auto & desc : columns_definition.columns_to_aggregate)
desc.createState();
// Start aggregations with current row
addRow(current);
if (columns_definition.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; // NOLINT
}
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; // NOLINT
}
}
else
{
addRow(current);
// Merge maps only for same rows
for (const auto & desc : columns_definition.maps_to_sum)
if (mergeMap(desc, current_row, current))
current_row_is_zero = false;
}
if (!current->isLast())
{
queue.next();
}
else
{
/// We get the next block from the corresponding source, if there is one.
queue.removeTop();
requestDataForInput(current.impl->order);
return;
}
}
/// 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();
last_chunk_sort_columns.clear();
is_finished = true;
}
}