void IndexForNativeFormat::read(ReadBuffer & istr, const NameSet & required_columns)
{
while (!istr.eof())
{
blocks.emplace_back();
IndexOfBlockForNativeFormat & block = blocks.back();
readVarUInt(block.num_columns, istr);
readVarUInt(block.num_rows, istr);
if (block.num_columns < required_columns.size())
throw Exception("Index contain less than required columns", ErrorCodes::INCORRECT_INDEX);
for (size_t i = 0; i < block.num_columns; ++i)
{
IndexOfOneColumnForNativeFormat column_index;
readBinary(column_index.name, istr);
readBinary(column_index.type, istr);
readBinary(column_index.location.offset_in_compressed_file, istr);
readBinary(column_index.location.offset_in_decompressed_block, istr);
if (required_columns.count(column_index.name))
block.columns.push_back(std::move(column_index));
}
if (block.columns.size() < required_columns.size())
throw Exception("Index contain less than required columns", ErrorCodes::INCORRECT_INDEX);
if (block.columns.size() > required_columns.size())
throw Exception("Index contain duplicate columns", ErrorCodes::INCORRECT_INDEX);
block.num_columns = block.columns.size();
}
}
NamesAndTypesList NamesAndTypesList::filter(const NameSet & names) const
{
NamesAndTypesList res;
for (const NameAndTypePair & column : *this)
{
if (names.count(column.name))
res.push_back(column);
}
return res;
}
/// Verifying that the function depends only on the specified columns
static bool isValidFunction(ASTPtr expression, const NameSet & columns)
{
for (size_t i = 0; i < expression->children.size(); ++i)
if (!isValidFunction(expression->children[i], columns))
return false;
if (const ASTIdentifier * identifier = typeid_cast<const ASTIdentifier *>(&*expression))
{
if (identifier->kind == ASTIdentifier::Kind::Column)
return columns.count(identifier->name);
}
return true;
}
std::vector<std::size_t> MergeTreeReadPool::fillPerPartInfo(
RangesInDataParts & parts, const ExpressionActionsPtr & prewhere_actions, const String & prewhere_column_name,
const bool check_columns)
{
std::vector<std::size_t> per_part_sum_marks;
for (const auto i : ext::range(0, parts.size()))
{
auto & part = parts[i];
/// Read marks for every data part.
size_t sum_marks = 0;
/// Ranges are in right-to-left order, due to 'reverse' in MergeTreeDataSelectExecutor.
for (const auto & range : part.ranges)
sum_marks += range.end - range.begin;
per_part_sum_marks.push_back(sum_marks);
per_part_columns_lock.push_back(std::make_unique<Poco::ScopedReadRWLock>(
part.data_part->columns_lock));
/// inject column names required for DEFAULT evaluation in current part
auto required_column_names = column_names;
const auto injected_columns = injectRequiredColumns(part.data_part, required_column_names);
auto should_reoder = !injected_columns.empty();
Names required_pre_column_names;
if (prewhere_actions)
{
/// collect columns required for PREWHERE evaluation
required_pre_column_names = prewhere_actions->getRequiredColumns();
/// there must be at least one column required for PREWHERE
if (required_pre_column_names.empty())
required_pre_column_names.push_back(required_column_names[0]);
/// PREWHERE columns may require some additional columns for DEFAULT evaluation
const auto injected_pre_columns = injectRequiredColumns(part.data_part, required_pre_column_names);
if (!injected_pre_columns.empty())
should_reoder = true;
/// will be used to distinguish between PREWHERE and WHERE columns when applying filter
const NameSet pre_name_set{
std::begin(required_pre_column_names), std::end(required_pre_column_names)
};
/** If expression in PREWHERE is not table column, then no need to return column with it to caller
* (because storage is expected only to read table columns).
*/
per_part_remove_prewhere_column.push_back(0 == pre_name_set.count(prewhere_column_name));
Names post_column_names;
for (const auto & name : required_column_names)
if (!pre_name_set.count(name))
post_column_names.push_back(name);
required_column_names = post_column_names;
}
else
per_part_remove_prewhere_column.push_back(false);
per_part_column_name_set.emplace_back(std::begin(required_column_names), std::end(required_column_names));
if (check_columns)
{
/** Under part->columns_lock check that all requested columns in part are of same type that in table.
* This could be violated during ALTER MODIFY.
*/
if (!required_pre_column_names.empty())
data.check(part.data_part->columns, required_pre_column_names);
if (!required_column_names.empty())
data.check(part.data_part->columns, required_column_names);
per_part_pre_columns.push_back(data.getColumnsList().addTypes(required_pre_column_names));
per_part_columns.push_back(data.getColumnsList().addTypes(required_column_names));
}
else
{
per_part_pre_columns.push_back(part.data_part->columns.addTypes(required_pre_column_names));
per_part_columns.push_back(part.data_part->columns.addTypes(required_column_names));
}
per_part_should_reorder.push_back(should_reoder);
this->parts.push_back({ part.data_part, part.part_index_in_query });
}
return per_part_sum_marks;
}
bool MergeTreeBlockInputStream::getNewTask()
try
{
/// Produce only one task
if (!is_first_task)
{
finish();
return false;
}
is_first_task = false;
Names pre_column_names, column_names = ordered_names;
bool remove_prewhere_column = false;
/// inject columns required for defaults evaluation
bool should_reorder = !injectRequiredColumns(storage, data_part, column_names).empty();
if (prewhere_actions)
{
pre_column_names = prewhere_actions->getRequiredColumns();
if (pre_column_names.empty())
pre_column_names.push_back(column_names[0]);
const auto injected_pre_columns = injectRequiredColumns(storage, data_part, pre_column_names);
if (!injected_pre_columns.empty())
should_reorder = true;
const NameSet pre_name_set(pre_column_names.begin(), pre_column_names.end());
/// If the expression in PREWHERE is not a column of the table, you do not need to output a column with it
/// (from storage expect to receive only the columns of the table).
remove_prewhere_column = !pre_name_set.count(prewhere_column);
Names post_column_names;
for (const auto & name : column_names)
if (!pre_name_set.count(name))
post_column_names.push_back(name);
column_names = post_column_names;
}
/// will be used to distinguish between PREWHERE and WHERE columns when applying filter
column_name_set = NameSet{column_names.begin(), column_names.end()};
if (check_columns)
{
/// Under owned_data_part->columns_lock we check that all requested columns are of the same type as in the table.
/// This may be not true in case of ALTER MODIFY.
if (!pre_column_names.empty())
storage.check(data_part->columns, pre_column_names);
if (!column_names.empty())
storage.check(data_part->columns, column_names);
pre_columns = storage.getColumnsList().addTypes(pre_column_names);
columns = storage.getColumnsList().addTypes(column_names);
}
else
{
pre_columns = data_part->columns.addTypes(pre_column_names);
columns = data_part->columns.addTypes(column_names);
}
/** @note you could simply swap `reverse` in if and else branches of MergeTreeDataSelectExecutor,
* and remove this reverse. */
MarkRanges remaining_mark_ranges = all_mark_ranges;
std::reverse(remaining_mark_ranges.begin(), remaining_mark_ranges.end());
auto size_predictor = (preferred_block_size_bytes == 0) ? nullptr
: std::make_unique<MergeTreeBlockSizePredictor>(data_part, ordered_names, data_part->storage.getSampleBlock());
task = std::make_unique<MergeTreeReadTask>(data_part, remaining_mark_ranges, part_index_in_query, ordered_names,
column_name_set, columns, pre_columns, remove_prewhere_column, should_reorder,
std::move(size_predictor));
if (!reader)
{
if (use_uncompressed_cache)
owned_uncompressed_cache = storage.context.getUncompressedCache();
owned_mark_cache = storage.context.getMarkCache();
reader = std::make_unique<MergeTreeReader>(
path, data_part, columns, owned_uncompressed_cache.get(),
owned_mark_cache.get(), save_marks_in_cache, storage,
all_mark_ranges, min_bytes_to_use_direct_io, max_read_buffer_size);
if (prewhere_actions)
pre_reader = std::make_unique<MergeTreeReader>(
path, data_part, pre_columns, owned_uncompressed_cache.get(),
owned_mark_cache.get(), save_marks_in_cache, storage,
all_mark_ranges, min_bytes_to_use_direct_io, max_read_buffer_size);
}
return true;
}
catch (...)
{
/// Suspicion of the broken part. A part is added to the queue for verification.
if (getCurrentExceptionCode() != ErrorCodes::MEMORY_LIMIT_EXCEEDED)
storage.reportBrokenPart(data_part->name);
throw;
}
void Join::joinBlockImpl(
Block & block,
const Names & key_names_left,
const NameSet & needed_key_names_right,
const Block & block_with_columns_to_add,
const Maps & maps_) const
{
size_t keys_size = key_names_left.size();
ColumnRawPtrs key_columns(keys_size);
/// Rare case, when keys are constant. To avoid code bloat, simply materialize them.
Columns materialized_columns;
materialized_columns.reserve(keys_size);
/// Memoize key columns to work with.
for (size_t i = 0; i < keys_size; ++i)
{
materialized_columns.emplace_back(recursiveRemoveLowCardinality(block.getByName(key_names_left[i]).column->convertToFullColumnIfConst()));
key_columns[i] = materialized_columns.back().get();
}
/// Keys with NULL value in any column won't join to anything.
ColumnPtr null_map_holder;
ConstNullMapPtr null_map{};
extractNestedColumnsAndNullMap(key_columns, null_map_holder, null_map);
size_t existing_columns = block.columns();
/** If you use FULL or RIGHT JOIN, then the columns from the "left" table must be materialized.
* Because if they are constants, then in the "not joined" rows, they may have different values
* - default values, which can differ from the values of these constants.
*/
if (getFullness(kind))
{
for (size_t i = 0; i < existing_columns; ++i)
{
block.getByPosition(i).column = block.getByPosition(i).column->convertToFullColumnIfConst();
/// If use_nulls, convert left columns (except keys) to Nullable.
if (use_nulls)
{
if (std::end(key_names_left) == std::find(key_names_left.begin(), key_names_left.end(), block.getByPosition(i).name))
convertColumnToNullable(block.getByPosition(i));
}
}
}
/** For LEFT/INNER JOIN, the saved blocks do not contain keys.
* For FULL/RIGHT JOIN, the saved blocks contain keys;
* but they will not be used at this stage of joining (and will be in `AdderNonJoined`), and they need to be skipped.
*/
size_t num_columns_to_skip = 0;
if (getFullness(kind))
num_columns_to_skip = keys_size;
/// Add new columns to the block.
size_t num_columns_to_add = sample_block_with_columns_to_add.columns();
MutableColumns added_columns;
added_columns.reserve(num_columns_to_add);
std::vector<std::pair<decltype(ColumnWithTypeAndName::type), decltype(ColumnWithTypeAndName::name)>> added_type_name;
added_type_name.reserve(num_columns_to_add);
std::vector<size_t> right_indexes;
right_indexes.reserve(num_columns_to_add);
for (size_t i = 0; i < num_columns_to_add; ++i)
{
const ColumnWithTypeAndName & src_column = sample_block_with_columns_to_add.safeGetByPosition(i);
/// Don't insert column if it's in left block or not explicitly required.
if (!block.has(src_column.name) && block_with_columns_to_add.has(src_column.name))
{
added_columns.push_back(src_column.column->cloneEmpty());
added_columns.back()->reserve(src_column.column->size());
added_type_name.emplace_back(src_column.type, src_column.name);
right_indexes.push_back(num_columns_to_skip + i);
}
}
size_t rows = block.rows();
std::unique_ptr<IColumn::Filter> filter;
bool filter_left_keys = (kind == ASTTableJoin::Kind::Inner || kind == ASTTableJoin::Kind::Right) && strictness == ASTTableJoin::Strictness::Any;
filter = std::make_unique<IColumn::Filter>(rows);
/// Used with ALL ... JOIN
IColumn::Offset current_offset = 0;
std::unique_ptr<IColumn::Offsets> offsets_to_replicate;
if (strictness == ASTTableJoin::Strictness::All)
offsets_to_replicate = std::make_unique<IColumn::Offsets>(rows);
switch (type)
{
#define M(TYPE) \
case Join::Type::TYPE: \
joinBlockImplType<KIND, STRICTNESS, typename KeyGetterForType<Join::Type::TYPE>::Type>(\
*maps_.TYPE, rows, key_columns, key_sizes, added_columns, null_map, \
filter, current_offset, offsets_to_replicate, right_indexes); \
break;
APPLY_FOR_JOIN_VARIANTS(M)
#undef M
default:
throw Exception("Unknown JOIN keys variant.", ErrorCodes::UNKNOWN_SET_DATA_VARIANT);
}
const auto added_columns_size = added_columns.size();
for (size_t i = 0; i < added_columns_size; ++i)
block.insert(ColumnWithTypeAndName(std::move(added_columns[i]), added_type_name[i].first, added_type_name[i].second));
/// If ANY INNER | RIGHT JOIN - filter all the columns except the new ones.
if (filter_left_keys)
for (size_t i = 0; i < existing_columns; ++i)
block.safeGetByPosition(i).column = block.safeGetByPosition(i).column->filter(*filter, -1);
ColumnUInt64::Ptr mapping;
/// Add join key columns from right block if they has different name.
for (size_t i = 0; i < key_names_right.size(); ++i)
{
auto & right_name = key_names_right[i];
auto & left_name = key_names_left[i];
if (needed_key_names_right.count(right_name) && !block.has(right_name))
{
const auto & col = block.getByName(left_name);
auto column = col.column;
if (!filter_left_keys)
{
if (!mapping)
{
auto mut_mapping = ColumnUInt64::create(column->size());
auto & data = mut_mapping->getData();
size_t size = column->size();
for (size_t j = 0; j < size; ++j)
data[j] = (*filter)[j] ? j : size;
mapping = std::move(mut_mapping);
}
auto mut_column = (*std::move(column)).mutate();
mut_column->insertDefault();
column = mut_column->index(*mapping, 0);
}
block.insert({column, col.type, right_name});
}
}
/// If ALL ... JOIN - we replicate all the columns except the new ones.
if (offsets_to_replicate)
{
for (size_t i = 0; i < existing_columns; ++i)
block.safeGetByPosition(i).column = block.safeGetByPosition(i).column->replicate(*offsets_to_replicate);
}
}
