ClickHouse/src/Interpreters/TableJoin.cpp
Nikolai Kochetov 07e835381c Fix build.
2020-09-08 14:06:36 +03:00

342 lines
10 KiB
C++

#include <Interpreters/TableJoin.h>
#include <Parsers/ASTExpressionList.h>
#include <Core/Settings.h>
#include <Core/Block.h>
#include <Core/ColumnsWithTypeAndName.h>
#include <Common/StringUtils/StringUtils.h>
#include <DataTypes/DataTypeNullable.h>
#include <DataStreams/materializeBlock.h>
namespace DB
{
TableJoin::TableJoin(const Settings & settings, VolumePtr tmp_volume_)
: size_limits(SizeLimits{settings.max_rows_in_join, settings.max_bytes_in_join, settings.join_overflow_mode})
, default_max_bytes(settings.default_max_bytes_in_join)
, join_use_nulls(settings.join_use_nulls)
, max_joined_block_rows(settings.max_joined_block_size_rows)
, join_algorithm(settings.join_algorithm)
, partial_merge_join_optimizations(settings.partial_merge_join_optimizations)
, partial_merge_join_rows_in_right_blocks(settings.partial_merge_join_rows_in_right_blocks)
, partial_merge_join_left_table_buffer_bytes(settings.partial_merge_join_left_table_buffer_bytes)
, max_files_to_merge(settings.join_on_disk_max_files_to_merge)
, temporary_files_codec(settings.temporary_files_codec)
, tmp_volume(tmp_volume_)
{
if (settings.partial_merge_join)
join_algorithm = JoinAlgorithm::PREFER_PARTIAL_MERGE;
}
void TableJoin::resetCollected()
{
key_names_left.clear();
key_names_right.clear();
key_asts_left.clear();
key_asts_right.clear();
columns_from_joined_table.clear();
columns_added_by_join.clear();
original_names.clear();
renames.clear();
}
void TableJoin::addUsingKey(const ASTPtr & ast)
{
key_names_left.push_back(ast->getColumnName());
key_names_right.push_back(ast->getAliasOrColumnName());
key_asts_left.push_back(ast);
key_asts_right.push_back(ast);
auto & right_key = key_names_right.back();
if (renames.count(right_key))
right_key = renames[right_key];
}
void TableJoin::addOnKeys(ASTPtr & left_table_ast, ASTPtr & right_table_ast)
{
key_names_left.push_back(left_table_ast->getColumnName());
key_names_right.push_back(right_table_ast->getAliasOrColumnName());
key_asts_left.push_back(left_table_ast);
key_asts_right.push_back(right_table_ast);
}
/// @return how many times right key appears in ON section.
size_t TableJoin::rightKeyInclusion(const String & name) const
{
if (hasUsing())
return 0;
size_t count = 0;
for (const auto & key_name : key_names_right)
if (name == key_name)
++count;
return count;
}
void TableJoin::deduplicateAndQualifyColumnNames(const NameSet & left_table_columns, const String & right_table_prefix)
{
NameSet joined_columns;
NamesAndTypesList dedup_columns;
for (auto & column : columns_from_joined_table)
{
if (joined_columns.count(column.name))
continue;
joined_columns.insert(column.name);
dedup_columns.push_back(column);
auto & inserted = dedup_columns.back();
/// Also qualify unusual column names - that does not look like identifiers.
if (left_table_columns.count(column.name) || !isValidIdentifierBegin(column.name.at(0)))
inserted.name = right_table_prefix + column.name;
original_names[inserted.name] = column.name;
if (inserted.name != column.name)
renames[column.name] = inserted.name;
}
columns_from_joined_table.swap(dedup_columns);
}
NameSet TableJoin::getQualifiedColumnsSet() const
{
NameSet out;
for (const auto & names : original_names)
out.insert(names.first);
return out;
}
NamesWithAliases TableJoin::getNamesWithAliases(const NameSet & required_columns) const
{
NamesWithAliases out;
for (const auto & column : required_columns)
{
auto it = original_names.find(column);
if (it != original_names.end())
out.emplace_back(it->second, it->first); /// {original_name, name}
}
return out;
}
ASTPtr TableJoin::leftKeysList() const
{
ASTPtr keys_list = std::make_shared<ASTExpressionList>();
keys_list->children = key_asts_left;
return keys_list;
}
ASTPtr TableJoin::rightKeysList() const
{
ASTPtr keys_list = std::make_shared<ASTExpressionList>();
if (hasOn())
keys_list->children = key_asts_right;
return keys_list;
}
Names TableJoin::requiredJoinedNames() const
{
NameSet required_columns_set(key_names_right.begin(), key_names_right.end());
for (const auto & joined_column : columns_added_by_join)
required_columns_set.insert(joined_column.name);
return Names(required_columns_set.begin(), required_columns_set.end());
}
NameSet TableJoin::requiredRightKeys() const
{
NameSet required;
for (const auto & name : key_names_right)
for (const auto & column : columns_added_by_join)
if (name == column.name)
required.insert(name);
return required;
}
NamesWithAliases TableJoin::getRequiredColumns(const Block & sample, const Names & action_required_columns) const
{
NameSet required_columns(action_required_columns.begin(), action_required_columns.end());
for (auto & column : requiredJoinedNames())
if (!sample.has(column))
required_columns.insert(column);
return getNamesWithAliases(required_columns);
}
void TableJoin::splitAdditionalColumns(const Block & sample_block, Block & block_keys, Block & block_others) const
{
block_others = materializeBlock(sample_block);
for (const String & column_name : key_names_right)
{
/// Extract right keys with correct keys order. There could be the same key names.
if (!block_keys.has(column_name))
{
auto & col = block_others.getByName(column_name);
block_keys.insert(col);
block_others.erase(column_name);
}
}
}
Block TableJoin::getRequiredRightKeys(const Block & right_table_keys, std::vector<String> & keys_sources) const
{
const Names & left_keys = keyNamesLeft();
const Names & right_keys = keyNamesRight();
NameSet required_keys(requiredRightKeys().begin(), requiredRightKeys().end());
Block required_right_keys;
for (size_t i = 0; i < right_keys.size(); ++i)
{
const String & right_key_name = right_keys[i];
if (required_keys.count(right_key_name) && !required_right_keys.has(right_key_name))
{
const auto & right_key = right_table_keys.getByName(right_key_name);
required_right_keys.insert(right_key);
keys_sources.push_back(left_keys[i]);
}
}
return required_right_keys;
}
bool TableJoin::leftBecomeNullable(const DataTypePtr & column_type) const
{
return forceNullableLeft() && column_type->canBeInsideNullable();
}
bool TableJoin::rightBecomeNullable(const DataTypePtr & column_type) const
{
return forceNullableRight() && column_type->canBeInsideNullable();
}
void TableJoin::addJoinedColumn(const NameAndTypePair & joined_column)
{
if (rightBecomeNullable(joined_column.type))
columns_added_by_join.emplace_back(NameAndTypePair(joined_column.name, makeNullable(joined_column.type)));
else
columns_added_by_join.push_back(joined_column);
}
void TableJoin::addJoinedColumnsAndCorrectNullability(ColumnsWithTypeAndName & columns) const
{
for (auto & col : columns)
{
/// Materialize column.
/// Column is not empty if it is constant, but after Join all constants will be materialized.
/// So, we need remove constants from header.
if (col.column)
col.column = nullptr;
if (leftBecomeNullable(col.type))
col.type = makeNullable(col.type);
}
for (const auto & col : columns_added_by_join)
{
auto res_type = col.type;
if (rightBecomeNullable(res_type))
res_type = makeNullable(res_type);
columns.emplace_back(nullptr, res_type, col.name);
}
}
bool TableJoin::sameJoin(const TableJoin * x, const TableJoin * y)
{
if (!x && !y)
return true;
if (!x || !y)
return false;
return x->table_join.kind == y->table_join.kind
&& x->table_join.strictness == y->table_join.strictness
&& x->key_names_left == y->key_names_left
&& x->key_names_right == y->key_names_right
&& x->columns_added_by_join == y->columns_added_by_join;
}
bool TableJoin::sameStrictnessAndKind(ASTTableJoin::Strictness strictness_, ASTTableJoin::Kind kind_) const
{
if (strictness_ == strictness() && kind_ == kind())
return true;
/// Compatibility: old ANY INNER == new SEMI LEFT
if (strictness_ == ASTTableJoin::Strictness::Semi && isLeft(kind_) &&
strictness() == ASTTableJoin::Strictness::RightAny && isInner(kind()))
return true;
if (strictness() == ASTTableJoin::Strictness::Semi && isLeft(kind()) &&
strictness_ == ASTTableJoin::Strictness::RightAny && isInner(kind_))
return true;
return false;
}
bool TableJoin::allowMergeJoin() const
{
bool is_any = (strictness() == ASTTableJoin::Strictness::Any);
bool is_all = (strictness() == ASTTableJoin::Strictness::All);
bool is_semi = (strictness() == ASTTableJoin::Strictness::Semi);
bool all_join = is_all && (isInner(kind()) || isLeft(kind()) || isRight(kind()) || isFull(kind()));
bool special_left = isLeft(kind()) && (is_any || is_semi);
return all_join || special_left;
}
bool TableJoin::needStreamWithNonJoinedRows() const
{
if (strictness() == ASTTableJoin::Strictness::Asof ||
strictness() == ASTTableJoin::Strictness::Semi)
return false;
return isRightOrFull(kind());
}
bool TableJoin::allowDictJoin(const String & dict_key, const Block & sample_block, Names & src_names, NamesAndTypesList & dst_columns) const
{
/// Support ALL INNER, [ANY | ALL | SEMI | ANTI] LEFT
if (!isLeft(kind()) && !(isInner(kind()) && strictness() == ASTTableJoin::Strictness::All))
return false;
const Names & right_keys = keyNamesRight();
if (right_keys.size() != 1)
return false;
/// TODO: support 'JOIN ... ON expr(dict_key) = table_key'
auto it_key = original_names.find(right_keys[0]);
if (it_key == original_names.end())
return false;
if (dict_key != it_key->second)
return false; /// JOIN key != Dictionary key
for (const auto & col : sample_block)
{
if (col.name == right_keys[0])
continue; /// do not extract key column
auto it = original_names.find(col.name);
if (it != original_names.end())
{
String original = it->second;
src_names.push_back(original);
dst_columns.push_back({col.name, col.type});
}
}
return true;
}
}