static void appendBlock(const Block & from, Block & to)
{
if (!to)
throw Exception("Cannot append to empty block", ErrorCodes::LOGICAL_ERROR);
assertBlocksHaveEqualStructure(from, to, "Buffer");
from.checkNumberOfRows();
to.checkNumberOfRows();
size_t rows = from.rows();
size_t bytes = from.bytes();
CurrentMetrics::add(CurrentMetrics::StorageBufferRows, rows);
CurrentMetrics::add(CurrentMetrics::StorageBufferBytes, bytes);
size_t old_rows = to.rows();
try
{
for (size_t column_no = 0, columns = to.columns(); column_no < columns; ++column_no)
{
const IColumn & col_from = *from.getByPosition(column_no).column.get();
MutableColumnPtr col_to = (*std::move(to.getByPosition(column_no).column)).mutate();
col_to->insertRangeFrom(col_from, 0, rows);
to.getByPosition(column_no).column = std::move(col_to);
}
}
catch (...)
{
/// Rollback changes.
try
{
/// Avoid "memory limit exceeded" exceptions during rollback.
TemporarilyDisableMemoryTracker temporarily_disable_memory_tracker;
for (size_t column_no = 0, columns = to.columns(); column_no < columns; ++column_no)
{
ColumnPtr & col_to = to.getByPosition(column_no).column;
if (col_to->size() != old_rows)
col_to = (*std::move(col_to)).mutate()->cut(0, old_rows);
}
}
catch (...)
{
/// In case when we cannot rollback, do not leave incorrect state in memory.
std::terminate();
}
throw;
}
}
void MergingSortedBlockInputStream::init(MutableColumns & merged_columns)
{
/// Read the first blocks, initialize the queue.
if (first)
{
first = false;
for (size_t i = 0; i < source_blocks.size(); ++i)
{
SharedBlockPtr & shared_block_ptr = source_blocks[i];
if (shared_block_ptr.get())
continue;
shared_block_ptr = new detail::SharedBlock(children[i]->read());
const size_t rows = shared_block_ptr->rows();
if (rows == 0)
continue;
if (expected_block_size < rows)
expected_block_size = std::min(rows, max_block_size);
cursors[i] = SortCursorImpl(*shared_block_ptr, description, i);
shared_block_ptr->all_columns = cursors[i].all_columns;
shared_block_ptr->sort_columns = cursors[i].sort_columns;
has_collation |= cursors[i].has_collation;
}
if (has_collation)
initQueue(queue_with_collation);
else
initQueue(queue_without_collation);
}
/// Let's check that all source blocks have the same structure.
for (const SharedBlockPtr & shared_block_ptr : source_blocks)
{
if (!*shared_block_ptr)
continue;
assertBlocksHaveEqualStructure(*shared_block_ptr, header, getName());
}
merged_columns.resize(num_columns);
for (size_t i = 0; i < num_columns; ++i)
{
merged_columns[i] = header.safeGetByPosition(i).column->cloneEmpty();
merged_columns[i]->reserve(expected_block_size);
}
}
