ClickHouse/src/Interpreters/TableJoin.h

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#pragma once
#include <Core/Names.h>
#include <Core/NamesAndTypes.h>
#include <Core/SettingsEnums.h>
#include <Parsers/ASTTablesInSelectQuery.h>
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#include <Interpreters/IJoin.h>
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#include <Interpreters/JoinUtils.h>
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#include <QueryPipeline/SizeLimits.h>
#include <DataTypes/getLeastSupertype.h>
#include <Interpreters/IKeyValueEntity.h>
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#include <Common/Exception.h>
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#include <Parsers/IAST_fwd.h>
#include <cstddef>
#include <unordered_map>
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#include <utility>
#include <memory>
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#include <base/types.h>
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#include <Common/logger_useful.h>
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namespace DB
{
class Context;
class ASTSelectQuery;
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struct DatabaseAndTableWithAlias;
class Block;
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class DictionaryJoinAdapter;
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class StorageJoin;
class StorageDictionary;
class IKeyValueEntity;
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struct ColumnWithTypeAndName;
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using ColumnsWithTypeAndName = std::vector<ColumnWithTypeAndName>;
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struct Settings;
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class IVolume;
using VolumePtr = std::shared_ptr<IVolume>;
class TableJoin
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{
public:
using NameToTypeMap = std::unordered_map<String, DataTypePtr>;
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/// Corresponds to one disjunct
struct JoinOnClause
{
Names key_names_left;
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Names key_names_right; /// Duplicating right key names are qualified
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ASTPtr on_filter_condition_left;
ASTPtr on_filter_condition_right;
JoinOnClause() = default;
std::pair<String, String> condColumnNames() const
{
std::pair<String, String> res;
if (on_filter_condition_left)
res.first = on_filter_condition_left->getColumnName();
if (on_filter_condition_right)
res.second = on_filter_condition_right->getColumnName();
return res;
}
size_t keysCount() const
{
assert(key_names_left.size() == key_names_right.size());
return key_names_right.size();
}
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String formatDebug() const
{
return fmt::format("Left keys: [{}] Right keys [{}] Condition columns: '{}', '{}'",
fmt::join(key_names_left, ", "), fmt::join(key_names_right, ", "),
condColumnNames().first, condColumnNames().second);
}
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};
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using Clauses = std::vector<JoinOnClause>;
private:
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/** Query of the form `SELECT expr(x) AS k FROM t1 ANY LEFT JOIN (SELECT expr(x) AS k FROM t2) USING k`
* The join is made by column k.
* During the JOIN,
* - in the "right" table, it will be available by alias `k`, since `Project` action for the subquery was executed.
* - in the "left" table, it will be accessible by the name `expr(x)`, since `Project` action has not been executed yet.
* You must remember both of these options.
*
* Query of the form `SELECT ... from t1 ANY LEFT JOIN (SELECT ... from t2) ON expr(t1 columns) = expr(t2 columns)`
* to the subquery will be added expression `expr(t2 columns)`.
* It's possible to use name `expr(t2 columns)`.
*/
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friend class TreeRewriter;
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SizeLimits size_limits;
const size_t default_max_bytes = 0;
const bool join_use_nulls = false;
const size_t max_joined_block_rows = 0;
MultiEnum<JoinAlgorithm> join_algorithm = MultiEnum<JoinAlgorithm>(JoinAlgorithm::AUTO);
const size_t partial_merge_join_rows_in_right_blocks = 0;
const size_t partial_merge_join_left_table_buffer_bytes = 0;
const size_t max_files_to_merge = 0;
const String temporary_files_codec = "LZ4";
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/// the limit has no technical reasons, it supposed to improve safety
const size_t MAX_DISJUNCTS = 16; /// NOLINT
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ASTs key_asts_left;
ASTs key_asts_right;
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Clauses clauses;
ASTTableJoin table_join;
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ASOFJoinInequality asof_inequality = ASOFJoinInequality::GreaterOrEquals;
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/// All columns which can be read from joined table. Duplicating names are qualified.
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NamesAndTypesList columns_from_joined_table;
/// Columns will be added to block by JOIN.
/// It's a subset of columns_from_joined_table
/// Note: without corrected Nullability or type, see correctedColumnsAddedByJoin
NamesAndTypesList columns_added_by_join;
/// Target type to convert key columns before join
NameToTypeMap left_type_map;
NameToTypeMap right_type_map;
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/// Name -> original name. Names are the same as in columns_from_joined_table list.
std::unordered_map<String, String> original_names;
/// Original name -> name. Only renamed columns.
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std::unordered_map<String, String> renames;
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VolumePtr tmp_volume;
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std::shared_ptr<StorageJoin> right_storage_join;
std::shared_ptr<IKeyValueEntity> right_kv_storage;
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std::string right_storage_name;
Names requiredJoinedNames() const;
/// Create converting actions and change key column names if required
ActionsDAGPtr applyKeyConvertToTable(
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const ColumnsWithTypeAndName & cols_src, const NameToTypeMap & type_mapping,
NameToNameMap & key_column_rename,
bool make_nullable) const;
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void addKey(const String & left_name, const String & right_name, const ASTPtr & left_ast, const ASTPtr & right_ast = nullptr);
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void assertHasOneOnExpr() const;
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/// Calculates common supertypes for corresponding join key columns.
template <typename LeftNamesAndTypes, typename RightNamesAndTypes>
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void inferJoinKeyCommonType(const LeftNamesAndTypes & left, const RightNamesAndTypes & right, bool allow_right, bool strict);
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NamesAndTypesList correctedColumnsAddedByJoin() const;
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public:
TableJoin() = default;
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TableJoin(const Settings & settings, VolumePtr tmp_volume_);
/// for StorageJoin
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TableJoin(SizeLimits limits, bool use_nulls, JoinKind kind, JoinStrictness strictness,
const Names & key_names_right)
: size_limits(limits)
, default_max_bytes(0)
, join_use_nulls(use_nulls)
, join_algorithm(JoinAlgorithm::HASH)
{
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clauses.emplace_back().key_names_right = key_names_right;
table_join.kind = kind;
table_join.strictness = strictness;
}
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JoinKind kind() const { return table_join.kind; }
JoinStrictness strictness() const { return table_join.strictness; }
bool sameStrictnessAndKind(JoinStrictness, JoinKind) const;
const SizeLimits & sizeLimits() const { return size_limits; }
VolumePtr getTemporaryVolume() { return tmp_volume; }
bool isEnabledAlgorithm(JoinAlgorithm val) const
{
/// When join_algorithm = 'default' (not specified by user) we use hash or direct algorithm.
/// It's behaviour that was initially supported by clickhouse.
bool is_enbaled_by_default = val == JoinAlgorithm::DEFAULT
|| val == JoinAlgorithm::HASH
|| val == JoinAlgorithm::DIRECT;
if (join_algorithm.isSet(JoinAlgorithm::DEFAULT) && is_enbaled_by_default)
return true;
return join_algorithm.isSet(val);
}
bool allowParallelHashJoin() const;
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bool joinUseNulls() const { return join_use_nulls; }
bool forceNullableRight() const { return join_use_nulls && isLeftOrFull(table_join.kind); }
bool forceNullableLeft() const { return join_use_nulls && isRightOrFull(table_join.kind); }
size_t defaultMaxBytes() const { return default_max_bytes; }
size_t maxJoinedBlockRows() const { return max_joined_block_rows; }
size_t maxRowsInRightBlock() const { return partial_merge_join_rows_in_right_blocks; }
size_t maxBytesInLeftBuffer() const { return partial_merge_join_left_table_buffer_bytes; }
size_t maxFilesToMerge() const { return max_files_to_merge; }
const String & temporaryFilesCodec() const { return temporary_files_codec; }
bool needStreamWithNonJoinedRows() const;
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bool oneDisjunct() const;
JoinOnClause & getOnlyClause() { assertHasOneOnExpr(); return clauses[0]; }
const JoinOnClause & getOnlyClause() const { assertHasOneOnExpr(); return clauses[0]; }
std::vector<JoinOnClause> & getClauses() { return clauses; }
const std::vector<JoinOnClause> & getClauses() const { return clauses; }
Names getAllNames(JoinTableSide side) const;
void resetCollected();
void addUsingKey(const ASTPtr & ast);
void addDisjunct();
void addOnKeys(ASTPtr & left_table_ast, ASTPtr & right_table_ast);
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/* Conditions for left/right table from JOIN ON section.
*
* Conditions for left and right tables stored separately and united with 'and' function into one column.
* For example for query:
* SELECT ... JOIN ... ON t1.id == t2.id AND expr11(t1) AND expr21(t2) AND expr12(t1) AND expr22(t2)
*
* We will build two new ASTs: `expr11(t1) AND expr12(t1)`, `expr21(t2) AND expr22(t2)`
* Such columns will be added and calculated for left and right tables respectively.
* Only rows where conditions are met (where new columns have non-zero value) will be joined.
*
* NOTE: non-equi condition containing columns from different tables (like `... ON t1.id = t2.id AND t1.val > t2.val)
* doesn't supported yet, it can be added later.
*/
void addJoinCondition(const ASTPtr & ast, bool is_left);
bool hasUsing() const { return table_join.using_expression_list != nullptr; }
bool hasOn() const { return table_join.on_expression != nullptr; }
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String getOriginalName(const String & column_name) const;
NamesWithAliases getNamesWithAliases(const NameSet & required_columns) const;
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NamesWithAliases getRequiredColumns(const Block & sample, const Names & action_required_columns) const;
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void deduplicateAndQualifyColumnNames(const NameSet & left_table_columns, const String & right_table_prefix);
size_t rightKeyInclusion(const String & name) const;
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NameSet requiredRightKeys() const;
bool leftBecomeNullable(const DataTypePtr & column_type) const;
bool rightBecomeNullable(const DataTypePtr & column_type) const;
void addJoinedColumn(const NameAndTypePair & joined_column);
template <typename TColumns>
void addJoinedColumnsAndCorrectTypesImpl(TColumns & left_columns, bool correct_nullability);
void addJoinedColumnsAndCorrectTypes(NamesAndTypesList & left_columns, bool correct_nullability);
void addJoinedColumnsAndCorrectTypes(ColumnsWithTypeAndName & left_columns, bool correct_nullability);
/// Calculate converting actions, rename key columns in required
/// For `USING` join we will convert key columns inplace and affect into types in the result table
/// For `JOIN ON` we will create new columns with converted keys to join by.
std::pair<ActionsDAGPtr, ActionsDAGPtr>
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createConvertingActions(
const ColumnsWithTypeAndName & left_sample_columns,
const ColumnsWithTypeAndName & right_sample_columns);
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void setAsofInequality(ASOFJoinInequality inequality) { asof_inequality = inequality; }
ASOFJoinInequality getAsofInequality() { return asof_inequality; }
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ASTPtr leftKeysList() const;
ASTPtr rightKeysList() const; /// For ON syntax only
const NamesAndTypesList & columnsFromJoinedTable() const { return columns_from_joined_table; }
Names columnsAddedByJoin() const
{
Names res;
for (const auto & col : columns_added_by_join)
res.push_back(col.name);
return res;
}
/// StorageJoin overrides key names (cause of different names qualification)
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void setRightKeys(const Names & keys) { getOnlyClause().key_names_right = keys; }
Block getRequiredRightKeys(const Block & right_table_keys, std::vector<String> & keys_sources) const;
String renamedRightColumnName(const String & name) const;
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void resetKeys();
void resetToCross();
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std::unordered_map<String, String> leftToRightKeyRemap() const;
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/// Remember storage name in case of joining with dictionary or another special storage
void setRightStorageName(const std::string & storage_name);
const std::string & getRightStorageName() const;
void setStorageJoin(std::shared_ptr<IKeyValueEntity> storage);
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void setStorageJoin(std::shared_ptr<StorageJoin> storage);
std::shared_ptr<StorageJoin> getStorageJoin() { return right_storage_join; }
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bool isSpecialStorage() const { return !right_storage_name.empty() || right_storage_join || right_kv_storage; }
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std::shared_ptr<IKeyValueEntity> getStorageKeyValue() { return right_kv_storage; }
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};
}