Block MongoDBBlockInputStream::readImpl()
{
if (all_read)
return {};
MutableColumns columns(description.sample_block.columns());
const size_t size = columns.size();
for (const auto i : ext::range(0, size))
columns[i] = description.sample_block.getByPosition(i).column->cloneEmpty();
size_t num_rows = 0;
while (num_rows < max_block_size)
{
Poco::MongoDB::ResponseMessage & response = cursor->next(*connection);
for (const auto & document : response.documents())
{
++num_rows;
for (const auto idx : ext::range(0, size))
{
const auto & name = description.sample_block.getByPosition(idx).name;
const Poco::MongoDB::Element::Ptr value = document->get(name);
if (value.isNull() || value->type() == Poco::MongoDB::ElementTraits<Poco::MongoDB::NullValue>::TypeId)
insertDefaultValue(*columns[idx], *description.sample_block.getByPosition(idx).column);
else
{
if (description.types[idx].second)
{
ColumnNullable & column_nullable = static_cast<ColumnNullable &>(*columns[idx]);
insertValue(column_nullable.getNestedColumn(), description.types[idx].first, *value, name);
column_nullable.getNullMapData().emplace_back(0);
}
else
insertValue(*columns[idx], description.types[idx].first, *value, name);
}
}
}
if (response.cursorID() == 0)
{
all_read = true;
break;
}
}
if (num_rows == 0)
return {};
return description.sample_block.cloneWithColumns(std::move(columns));
}
Block MongoDBBlockInputStream::readImpl()
{
if (all_read)
return {};
Block block = description.sample_block.cloneEmpty();
/// cache pointers returned by the calls to getByPosition
std::vector<IColumn *> columns(block.columns());
const size_t size = columns.size();
for (const auto i : ext::range(0, size))
columns[i] = block.getByPosition(i).column.get();
size_t num_rows = 0;
while (num_rows < max_block_size)
{
Poco::MongoDB::ResponseMessage & response = cursor->next(*connection);
for (const auto & document : response.documents())
{
++num_rows;
for (const auto idx : ext::range(0, size))
{
const auto & name = description.names[idx];
const Poco::MongoDB::Element::Ptr value = document->get(name);
if (value.isNull())
insertDefaultValue(columns[idx], *description.sample_columns[idx]);
else
insertValue(columns[idx], description.types[idx], *value, name);
}
}
if (response.cursorID() == 0)
{
all_read = true;
break;
}
}
if (num_rows == 0)
return {};
return block;
}