ClickHouse/dbms/src/Interpreters/Set.h
2018-07-04 20:28:52 +03:00

196 lines
6.3 KiB
C++

#pragma once
#include <shared_mutex>
#include <Core/Block.h>
#include <DataStreams/SizeLimits.h>
#include <DataTypes/IDataType.h>
#include <Interpreters/SetVariants.h>
#include <Interpreters/Context.h>
#include <Parsers/IAST.h>
#include <Storages/MergeTree/BoolMask.h>
#include <common/logger_useful.h>
namespace DB
{
struct Range;
class FieldWithInfinity;
class IFunctionBase;
using FunctionBasePtr = std::shared_ptr<IFunctionBase>;
/** Data structure for implementation of IN expression.
*/
class Set
{
public:
/// 'fill_set_elements': in addition to hash table
/// (that is useful only for checking that some value is in the set and may not store the original values),
/// store all set elements in explicit form.
/// This is needed for subsequent use for index.
Set(const SizeLimits & limits, bool fill_set_elements)
: log(&Logger::get("Set")),
limits(limits), fill_set_elements(fill_set_elements)
{
}
bool empty() const { return data.empty(); }
/** Set can be created either from AST or from a stream of data (subquery result).
*/
/** Create a Set from expression (specified literally in the query).
* 'types' - types of what are on the left hand side of IN.
* 'node' - list of values: 1, 2, 3 or list of tuples: (1, 2), (3, 4), (5, 6).
* 'fill_set_elements' - if true, fill vector of elements. For primary key to work.
*/
void createFromAST(const DataTypes & types, ASTPtr node, const Context & context);
/** Create a Set from stream.
* Call setHeader, then call insertFromBlock for each block.
*/
void setHeader(const Block & header);
/// Returns false, if some limit was exceeded and no need to insert more data.
bool insertFromBlock(const Block & block);
/** For columns of 'block', check belonging of corresponding rows to the set.
* Return UInt8 column with the result.
*/
ColumnPtr execute(const Block & block, bool negative) const;
size_t getTotalRowCount() const { return data.getTotalRowCount(); }
size_t getTotalByteCount() const { return data.getTotalByteCount(); }
const DataTypes & getDataTypes() const { return data_types; }
bool hasExplicitSetElements() const { return fill_set_elements; }
const Columns & getSetElements() const { return set_elements; }
private:
size_t keys_size = 0;
Sizes key_sizes;
SetVariants data;
/** How IN works with Nullable types.
*
* For simplicity reasons, all NULL values and any tuples with at least one NULL element are ignored in the Set.
* And for left hand side values, that are NULLs or contain any NULLs, we return 0 (means that element is not in Set).
*
* If we want more standard compliant behaviour, we must return NULL
* if lhs is NULL and set is not empty or if lhs is not in set, but set contains at least one NULL.
* It is more complicated with tuples.
* For example,
* (1, NULL, 2) IN ((1, NULL, 3)) must return 0,
* but (1, NULL, 2) IN ((1, 1111, 2)) must return NULL.
*
* We have not implemented such sophisticated behaviour.
*/
/** The data types from which the set was created.
* When checking for belonging to a set, the types of columns to be checked must match with them.
*/
DataTypes data_types;
Logger * log;
/// Limitations on the maximum size of the set
SizeLimits limits;
/// Do we need to additionally store all elements of the set in explicit form for subsequent use for index.
bool fill_set_elements;
/// If in the left part columns contains the same types as the elements of the set.
void executeOrdinary(
const ColumnRawPtrs & key_columns,
ColumnUInt8::Container & vec_res,
bool negative,
const PaddedPODArray<UInt8> * null_map) const;
/// Collected elements of `Set`.
/// It is necessary for the index to work on the primary key in the IN statement.
Columns set_elements;
/** Protects work with the set in the functions `insertFromBlock` and `execute`.
* These functions can be called simultaneously from different threads only when using StorageSet,
* and StorageSet calls only these two functions.
* Therefore, the rest of the functions for working with set are not protected.
*/
mutable std::shared_mutex rwlock;
template <typename Method>
void insertFromBlockImpl(
Method & method,
const ColumnRawPtrs & key_columns,
size_t rows,
SetVariants & variants,
ConstNullMapPtr null_map,
ColumnUInt8::Container * out_filter);
template <typename Method, bool has_null_map, bool build_filter>
void insertFromBlockImplCase(
Method & method,
const ColumnRawPtrs & key_columns,
size_t rows,
SetVariants & variants,
ConstNullMapPtr null_map,
ColumnUInt8::Container * out_filter);
template <typename Method>
void executeImpl(
Method & method,
const ColumnRawPtrs & key_columns,
ColumnUInt8::Container & vec_res,
bool negative,
size_t rows,
ConstNullMapPtr null_map) const;
template <typename Method, bool has_null_map>
void executeImplCase(
Method & method,
const ColumnRawPtrs & key_columns,
ColumnUInt8::Container & vec_res,
bool negative,
size_t rows,
ConstNullMapPtr null_map) const;
};
using SetPtr = std::shared_ptr<Set>;
using ConstSetPtr = std::shared_ptr<const Set>;
using Sets = std::vector<SetPtr>;
class IFunction;
using FunctionPtr = std::shared_ptr<IFunction>;
/// Class for mayBeTrueInRange function.
class MergeTreeSetIndex
{
public:
/** Mapping for tuple positions from Set::set_elements to
* position of pk index and functions chain applied to this column.
*/
struct KeyTuplePositionMapping
{
size_t tuple_index;
size_t key_index;
std::vector<FunctionBasePtr> functions;
};
MergeTreeSetIndex(const Columns & set_elements, std::vector<KeyTuplePositionMapping> && indexes_mapping_);
size_t size() const { return ordered_set.at(0)->size(); }
BoolMask mayBeTrueInRange(const std::vector<Range> & key_ranges, const DataTypes & data_types);
private:
Columns ordered_set;
std::vector<KeyTuplePositionMapping> indexes_mapping;
};
}