ClickHouse/src/Interpreters/join_common.cpp

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#include <Interpreters/join_common.h>
#include <Interpreters/TableJoin.h>
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#include <Interpreters/ActionsDAG.h>
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#include <Columns/ColumnNullable.h>
#include <Columns/ColumnLowCardinality.h>
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#include <DataTypes/DataTypeNullable.h>
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#include <DataTypes/DataTypeLowCardinality.h>
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#include <DataTypes/getLeastSupertype.h>
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#include <DataStreams/materializeBlock.h>
#include <IO/WriteHelpers.h>
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namespace DB
{
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namespace ErrorCodes
{
extern const int TYPE_MISMATCH;
extern const int LOGICAL_ERROR;
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}
namespace
{
void changeNullability(MutableColumnPtr & mutable_column)
{
ColumnPtr column = std::move(mutable_column);
if (const auto * nullable = checkAndGetColumn<ColumnNullable>(*column))
column = nullable->getNestedColumnPtr();
else
column = makeNullable(column);
mutable_column = IColumn::mutate(std::move(column));
}
ColumnPtr changeLowCardinality(const ColumnPtr & column, const ColumnPtr & dst_sample)
{
if (dst_sample->lowCardinality())
{
MutableColumnPtr lc = dst_sample->cloneEmpty();
typeid_cast<ColumnLowCardinality &>(*lc).insertRangeFromFullColumn(*column, 0, column->size());
return lc;
}
return column->convertToFullColumnIfLowCardinality();
}
}
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namespace JoinCommon
{
bool canBecomeNullable(const DataTypePtr & type)
{
bool can_be_inside = type->canBeInsideNullable();
if (const auto * low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(type.get()))
can_be_inside |= low_cardinality_type->getDictionaryType()->canBeInsideNullable();
return can_be_inside;
}
/// Add nullability to type.
/// Note: LowCardinality(T) transformed to LowCardinality(Nullable(T))
DataTypePtr convertTypeToNullable(const DataTypePtr & type)
{
if (const auto * low_cardinality_type = typeid_cast<const DataTypeLowCardinality *>(type.get()))
{
const auto & dict_type = low_cardinality_type->getDictionaryType();
if (dict_type->canBeInsideNullable())
return std::make_shared<DataTypeLowCardinality>(makeNullable(dict_type));
}
return makeNullable(type);
}
void convertColumnToNullable(ColumnWithTypeAndName & column, bool remove_low_card)
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{
if (remove_low_card && column.type->lowCardinality())
{
column.column = recursiveRemoveLowCardinality(column.column);
column.type = recursiveRemoveLowCardinality(column.type);
}
if (column.type->isNullable() || !canBecomeNullable(column.type))
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return;
column.type = convertTypeToNullable(column.type);
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if (column.column)
{
if (column.column->lowCardinality())
{
/// Convert nested to nullable, not LowCardinality itself
auto new_col = column.column->cloneEmpty();
new_col->insertRangeFrom(*column.column, 0, column.column->size());
/// How to call non-constant methon on ColumnPtr without a copy?
assert_cast<ColumnLowCardinality *>(new_col.get())->nestedToNullable();
column.column = std::move(new_col);
}
else
column.column = makeNullable(column.column);
}
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}
void convertColumnsToNullable(Block & block, size_t starting_pos)
{
for (size_t i = starting_pos; i < block.columns(); ++i)
convertColumnToNullable(block.getByPosition(i));
}
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/// @warning It assumes that every NULL has default value in nested column (or it does not matter)
void removeColumnNullability(ColumnWithTypeAndName & column)
{
if (!column.type->isNullable())
return;
column.type = static_cast<const DataTypeNullable &>(*column.type).getNestedType();
if (column.column)
{
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const auto * nullable_column = checkAndGetColumn<ColumnNullable>(*column.column);
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ColumnPtr nested_column = nullable_column->getNestedColumnPtr();
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MutableColumnPtr mutable_column = IColumn::mutate(std::move(nested_column));
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column.column = std::move(mutable_column);
}
}
/// Change both column nullability and low cardinality
void changeColumnRepresentation(const ColumnPtr & src_column, ColumnPtr & dst_column)
{
bool nullable_src = src_column->isNullable();
bool nullable_dst = dst_column->isNullable();
ColumnPtr dst_not_null = JoinCommon::emptyNotNullableClone(dst_column);
bool lowcard_src = JoinCommon::emptyNotNullableClone(src_column)->lowCardinality();
bool lowcard_dst = dst_not_null->lowCardinality();
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bool change_lowcard = lowcard_src != lowcard_dst;
if (nullable_src && !nullable_dst)
{
const auto * nullable = checkAndGetColumn<ColumnNullable>(*src_column);
if (change_lowcard)
dst_column = changeLowCardinality(nullable->getNestedColumnPtr(), dst_column);
else
dst_column = nullable->getNestedColumnPtr();
}
else if (!nullable_src && nullable_dst)
{
if (change_lowcard)
dst_column = makeNullable(changeLowCardinality(src_column, dst_not_null));
else
dst_column = makeNullable(src_column);
}
else /// same nullability
{
if (change_lowcard)
{
if (const auto * nullable = checkAndGetColumn<ColumnNullable>(*src_column))
{
dst_column = makeNullable(changeLowCardinality(nullable->getNestedColumnPtr(), dst_not_null));
assert_cast<ColumnNullable &>(*dst_column->assumeMutable()).applyNullMap(nullable->getNullMapColumn());
}
else
dst_column = changeLowCardinality(src_column, dst_not_null);
}
else
dst_column = src_column;
}
}
ColumnPtr emptyNotNullableClone(const ColumnPtr & column)
{
if (column->isNullable())
return checkAndGetColumn<ColumnNullable>(*column)->getNestedColumnPtr()->cloneEmpty();
return column->cloneEmpty();
}
ColumnRawPtrs materializeColumnsInplace(Block & block, const Names & names)
{
ColumnRawPtrs ptrs;
ptrs.reserve(names.size());
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for (const auto & column_name : names)
{
auto & column = block.getByName(column_name).column;
column = recursiveRemoveLowCardinality(column->convertToFullColumnIfConst());
ptrs.push_back(column.get());
}
return ptrs;
}
Columns materializeColumns(const Block & block, const Names & names)
{
Columns materialized;
materialized.reserve(names.size());
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for (const auto & column_name : names)
{
const auto & src_column = block.getByName(column_name).column;
materialized.emplace_back(recursiveRemoveLowCardinality(src_column->convertToFullColumnIfConst()));
}
return materialized;
}
ColumnRawPtrs getRawPointers(const Columns & columns)
{
ColumnRawPtrs ptrs;
ptrs.reserve(columns.size());
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for (const auto & column : columns)
ptrs.push_back(column.get());
return ptrs;
}
void removeLowCardinalityInplace(Block & block)
{
for (size_t i = 0; i < block.columns(); ++i)
{
auto & col = block.getByPosition(i);
col.column = recursiveRemoveLowCardinality(col.column);
col.type = recursiveRemoveLowCardinality(col.type);
}
}
void removeLowCardinalityInplace(Block & block, const Names & names, bool change_type)
{
for (const String & column_name : names)
{
auto & col = block.getByName(column_name);
col.column = recursiveRemoveLowCardinality(col.column);
if (change_type)
col.type = recursiveRemoveLowCardinality(col.type);
}
}
void restoreLowCardinalityInplace(Block & block)
{
for (size_t i = 0; i < block.columns(); ++i)
{
auto & col = block.getByPosition(i);
if (col.type->lowCardinality() && col.column && !col.column->lowCardinality())
col.column = changeLowCardinality(col.column, col.type->createColumn());
}
}
ColumnRawPtrs extractKeysForJoin(const Block & block_keys, const Names & key_names)
{
size_t keys_size = key_names.size();
ColumnRawPtrs key_columns(keys_size);
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for (size_t i = 0; i < keys_size; ++i)
{
const String & column_name = key_names[i];
key_columns[i] = block_keys.getByName(column_name).column.get();
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/// We will join only keys, where all components are not NULL.
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if (const auto * nullable = checkAndGetColumn<ColumnNullable>(*key_columns[i]))
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key_columns[i] = &nullable->getNestedColumn();
}
return key_columns;
}
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void checkTypesOfKeys(const Block & block_left, const Names & key_names_left, const Block & block_right, const Names & key_names_right)
{
size_t keys_size = key_names_left.size();
for (size_t i = 0; i < keys_size; ++i)
{
DataTypePtr left_type = removeNullable(recursiveRemoveLowCardinality(block_left.getByName(key_names_left[i]).type));
DataTypePtr right_type = removeNullable(recursiveRemoveLowCardinality(block_right.getByName(key_names_right[i]).type));
if (!left_type->equals(*right_type))
throw Exception("Type mismatch of columns to JOIN by: "
+ key_names_left[i] + " " + left_type->getName() + " at left, "
+ key_names_right[i] + " " + right_type->getName() + " at right",
ErrorCodes::TYPE_MISMATCH);
}
}
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void createMissedColumns(Block & block)
{
for (size_t i = 0; i < block.columns(); ++i)
{
auto & column = block.getByPosition(i);
if (!column.column)
column.column = column.type->createColumn();
}
}
/// Append totals from right to left block, correct types if needed
void joinTotals(const Block & totals, const Block & columns_to_add, const TableJoin & table_join, Block & block)
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{
if (table_join.forceNullableLeft())
convertColumnsToNullable(block);
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if (Block totals_without_keys = totals)
{
for (const auto & name : table_join.keyNamesRight())
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totals_without_keys.erase(totals_without_keys.getPositionByName(name));
for (auto & col : totals_without_keys)
{
if (table_join.rightBecomeNullable(col.type))
JoinCommon::convertColumnToNullable(col);
/// In case of arrayJoin it can be not one row
if (col.column->size() != 1)
col.column = col.column->cloneResized(1);
}
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for (size_t i = 0; i < totals_without_keys.columns(); ++i)
block.insert(totals_without_keys.safeGetByPosition(i));
}
else
{
/// We will join empty `totals` - from one row with the default values.
for (size_t i = 0; i < columns_to_add.columns(); ++i)
{
const auto & col = columns_to_add.getByPosition(i);
if (block.has(col.name))
{
/// For StorageJoin we discarded table qualifiers, so some names may clash
continue;
}
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block.insert({
col.type->createColumnConstWithDefaultValue(1)->convertToFullColumnIfConst(),
col.type,
col.name});
}
}
}
void addDefaultValues(IColumn & column, const DataTypePtr & type, size_t count)
{
column.reserve(column.size() + count);
for (size_t i = 0; i < count; ++i)
type->insertDefaultInto(column);
}
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bool typesEqualUpToNullability(DataTypePtr left_type, DataTypePtr right_type)
{
DataTypePtr left_type_strict = removeNullable(recursiveRemoveLowCardinality(left_type));
DataTypePtr right_type_strict = removeNullable(recursiveRemoveLowCardinality(right_type));
return left_type_strict->equals(*right_type_strict);
}
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}
NotJoined::NotJoined(const TableJoin & table_join, const Block & saved_block_sample_, const Block & right_sample_block,
const Block & result_sample_block_)
: saved_block_sample(saved_block_sample_)
, result_sample_block(materializeBlock(result_sample_block_))
{
std::vector<String> tmp;
Block right_table_keys;
Block sample_block_with_columns_to_add;
table_join.splitAdditionalColumns(right_sample_block, right_table_keys, sample_block_with_columns_to_add);
Block required_right_keys = table_join.getRequiredRightKeys(right_table_keys, tmp);
std::unordered_map<size_t, size_t> left_to_right_key_remap;
if (table_join.hasUsing())
{
for (size_t i = 0; i < table_join.keyNamesLeft().size(); ++i)
{
const String & left_key_name = table_join.keyNamesLeft()[i];
const String & right_key_name = table_join.keyNamesRight()[i];
size_t left_key_pos = result_sample_block.getPositionByName(left_key_name);
size_t right_key_pos = saved_block_sample.getPositionByName(right_key_name);
if (!required_right_keys.has(right_key_name))
left_to_right_key_remap[left_key_pos] = right_key_pos;
}
}
/// result_sample_block: left_sample_block + left expressions, right not key columns, required right keys
size_t left_columns_count = result_sample_block.columns() -
sample_block_with_columns_to_add.columns() - required_right_keys.columns();
for (size_t left_pos = 0; left_pos < left_columns_count; ++left_pos)
{
/// We need right 'x' for 'RIGHT JOIN ... USING(x)'.
if (left_to_right_key_remap.count(left_pos))
{
size_t right_key_pos = left_to_right_key_remap[left_pos];
setRightIndex(right_key_pos, left_pos);
}
else
column_indices_left.emplace_back(left_pos);
}
for (size_t right_pos = 0; right_pos < saved_block_sample.columns(); ++right_pos)
{
const String & name = saved_block_sample.getByPosition(right_pos).name;
if (!result_sample_block.has(name))
continue;
size_t result_position = result_sample_block.getPositionByName(name);
/// Don't remap left keys twice. We need only qualified right keys here
if (result_position < left_columns_count)
continue;
setRightIndex(right_pos, result_position);
}
if (column_indices_left.size() + column_indices_right.size() + same_result_keys.size() != result_sample_block.columns())
throw Exception("Error in columns mapping in RIGHT|FULL JOIN. Left: " + toString(column_indices_left.size()) +
", right: " + toString(column_indices_right.size()) +
", same: " + toString(same_result_keys.size()) +
", result: " + toString(result_sample_block.columns()),
ErrorCodes::LOGICAL_ERROR);
}
void NotJoined::setRightIndex(size_t right_pos, size_t result_position)
{
if (!column_indices_right.count(right_pos))
{
column_indices_right[right_pos] = result_position;
extractColumnChanges(right_pos, result_position);
}
else
same_result_keys[result_position] = column_indices_right[right_pos];
}
void NotJoined::extractColumnChanges(size_t right_pos, size_t result_pos)
{
const auto & src = saved_block_sample.getByPosition(right_pos).column;
const auto & dst = result_sample_block.getByPosition(result_pos).column;
if (!src->isNullable() && dst->isNullable())
right_nullability_adds.push_back(right_pos);
if (src->isNullable() && !dst->isNullable())
right_nullability_removes.push_back(right_pos);
ColumnPtr src_not_null = JoinCommon::emptyNotNullableClone(src);
ColumnPtr dst_not_null = JoinCommon::emptyNotNullableClone(dst);
if (src_not_null->lowCardinality() != dst_not_null->lowCardinality())
right_lowcard_changes.push_back({right_pos, dst_not_null});
}
void NotJoined::correctLowcardAndNullability(MutableColumns & columns_right)
{
for (size_t pos : right_nullability_removes)
changeNullability(columns_right[pos]);
for (auto & [pos, dst_sample] : right_lowcard_changes)
columns_right[pos] = changeLowCardinality(std::move(columns_right[pos]), dst_sample)->assumeMutable();
for (size_t pos : right_nullability_adds)
changeNullability(columns_right[pos]);
}
void NotJoined::addLeftColumns(Block & block, size_t rows_added) const
{
for (size_t pos : column_indices_left)
{
auto & col = block.getByPosition(pos);
auto mut_col = col.column->cloneEmpty();
JoinCommon::addDefaultValues(*mut_col, col.type, rows_added);
col.column = std::move(mut_col);
}
}
void NotJoined::addRightColumns(Block & block, MutableColumns & columns_right) const
{
for (const auto & pr : column_indices_right)
{
auto & right_column = columns_right[pr.first];
auto & result_column = block.getByPosition(pr.second).column;
#ifndef NDEBUG
if (result_column->getName() != right_column->getName())
throw Exception("Wrong columns assign in RIGHT|FULL JOIN: " + result_column->getName() +
" " + right_column->getName(), ErrorCodes::LOGICAL_ERROR);
#endif
result_column = std::move(right_column);
}
}
void NotJoined::copySameKeys(Block & block) const
{
for (const auto & pr : same_result_keys)
{
auto & src_column = block.getByPosition(pr.second).column;
auto & dst_column = block.getByPosition(pr.first).column;
JoinCommon::changeColumnRepresentation(src_column, dst_column);
}
}
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}