ClickHouse/dbms/src/Storages/MergeTree/IMergeTreeDataPart.h
2019-12-10 00:21:17 +03:00

359 lines
14 KiB
C++

#pragma once
#include <DataStreams/IBlockInputStream.h>
#include <Core/Row.h>
#include <Core/Block.h>
#include <Core/Types.h>
#include <Core/NamesAndTypes.h>
#include <Storages/IStorage.h>
#include <Storages/MergeTree/MergeTreeIndexGranularity.h>
#include <Storages/MergeTree/MergeTreeIndexGranularityInfo.h>
#include <Storages/MergeTree/MergeTreeIndices.h>
#include <Storages/MergeTree/MergeTreePartInfo.h>
#include <Storages/MergeTree/MergeTreePartition.h>
#include <Storages/MergeTree/MergeTreeDataPartChecksum.h>
#include <Storages/MergeTree/MergeTreeDataPartTTLInfo.h>
#include <Storages/MergeTree/KeyCondition.h>
// #include <Storages/MergeTree/IMergeTreeDataPart_fwd.h>
// #include <Storages/MergeTree/IMergeTreeReader.h>
// #include <Storages/MergeTree/IMergeTreeDataPartWriter.h>
// #include <Storages/MergeTree/MergeTreeWriter.h>
// #include <Storages/MergeTree/MergeTreeDataPartWide.h>
#include <Columns/IColumn.h>
#include <Storages/MergeTree/MergeTreeReaderSettings.h>
#include <Poco/Path.h>
#include <shared_mutex>
namespace DB
{
struct ColumnSize;
class MergeTreeData;
class IMergeTreeReader;
class IMergeTreeDataPartWriter;
namespace ErrorCodes
{
extern const int NOT_IMPLEMETED;
}
class IMergeTreeDataPart : public std::enable_shared_from_this<IMergeTreeDataPart>
{
public:
using Checksums = MergeTreeDataPartChecksums;
using Checksum = MergeTreeDataPartChecksums::Checksum;
using ValueSizeMap = std::map<std::string, double>;
using MergeTreeReaderPtr = std::unique_ptr<IMergeTreeReader>;
using MergeTreeWriterPtr = std::unique_ptr<IMergeTreeDataPartWriter>;
using ColumnSizeByName = std::unordered_map<std::string, ColumnSize>;
virtual MergeTreeReaderPtr getReader(
const NamesAndTypesList & columns_,
const MarkRanges & mark_ranges,
UncompressedCache * uncompressed_cache,
MarkCache * mark_cache,
const ReaderSettings & reader_settings_,
const ValueSizeMap & avg_value_size_hints_ = ValueSizeMap{},
const ReadBufferFromFileBase::ProfileCallback & profile_callback_ = ReadBufferFromFileBase::ProfileCallback{}) const = 0;
virtual MergeTreeWriterPtr getWriter(
const NamesAndTypesList & columns_list,
const std::vector<MergeTreeIndexPtr> & indices_to_recalc,
const CompressionCodecPtr & default_codec_,
const WriterSettings & writer_settings,
const MergeTreeIndexGranularity & computed_index_granularity = {}) const = 0;
virtual bool isStoredOnDisk() const = 0;
virtual bool supportsVerticalMerge() const { return false; }
/// NOTE: Returns zeros if column files are not found in checksums.
/// NOTE: You must ensure that no ALTERs are in progress when calculating ColumnSizes.
/// (either by locking columns_lock, or by locking table structure).
virtual ColumnSize getColumnSize(const String & /* name */, const IDataType & /* type */) const { return {}; }
virtual ColumnSize getTotalColumnsSize() const { return {}; }
/// Returns the name of a column with minimum compressed size (as returned by getColumnSize()).
/// If no checksums are present returns the name of the first physically existing column.
virtual String getColumnNameWithMinumumCompressedSize() const { return columns.front().name; }
virtual ~IMergeTreeDataPart();
// virtual Checksums check(
// bool require_checksums,
// const DataTypes & primary_key_data_types, /// Check the primary key. If it is not necessary, pass an empty array.
// const MergeTreeIndices & indices = {}, /// Check skip indices
// std::function<bool()> is_cancelled = []{ return false; })
// {
// return {};
// }
using ColumnToSize = std::map<std::string, UInt64>;
virtual void accumulateColumnSizes(ColumnToSize & column_to_size) const;
using Type = MergeTreeDataPartType;
virtual Type getType() const = 0;
static String typeToString(Type type);
String getTypeName() { return typeToString(getType()); }
IMergeTreeDataPart(
const MergeTreeData & storage_,
const String & name_,
const MergeTreePartInfo & info_,
const DiskSpace::DiskPtr & disk = {},
const std::optional<String> & relative_path = {});
IMergeTreeDataPart(
MergeTreeData & storage_,
const String & name_,
const DiskSpace::DiskPtr & disk = {},
const std::optional<String> & relative_path = {});
void assertOnDisk() const;
void remove() const;
/// Initialize columns (from columns.txt if exists, or create from column files if not).
/// Load checksums from checksums.txt if exists. Load index if required.
void loadColumnsChecksumsIndexes(bool require_columns_checksums, bool check_consistency);
String getMarksFileExtension() const { return index_granularity_info.marks_file_extension; }
/// Generate the new name for this part according to `new_part_info` and min/max dates from the old name.
/// This is useful when you want to change e.g. block numbers or the mutation version of the part.
String getNewName(const MergeTreePartInfo & new_part_info) const;
// Block sample_block;
std::optional<size_t> getColumnPosition(const String & column_name) const;
bool contains(const IMergeTreeDataPart & other) const { return info.contains(other.info); }
/// If the partition key includes date column (a common case), these functions will return min and max values for this column.
DayNum getMinDate() const;
DayNum getMaxDate() const;
/// otherwise, if the partition key includes dateTime column (also a common case), these functions will return min and max values for this column.
time_t getMinTime() const;
time_t getMaxTime() const;
void setColumns(const NamesAndTypesList & columns_);
bool isEmpty() const { return rows_count == 0; }
const MergeTreeData & storage;
String name;
MergeTreePartInfo info;
MergeTreeIndexGranularityInfo index_granularity_info;
DiskSpace::DiskPtr disk;
mutable String relative_path;
size_t rows_count = 0;
std::atomic<UInt64> bytes_on_disk {0}; /// 0 - if not counted;
/// Is used from several threads without locks (it is changed with ALTER).
/// May not contain size of checksums.txt and columns.txt
time_t modification_time = 0;
/// When the part is removed from the working set. Changes once.
mutable std::atomic<time_t> remove_time { std::numeric_limits<time_t>::max() };
/// If true, the destructor will delete the directory with the part.
bool is_temp = false;
/// If true it means that there are no ZooKeeper node for this part, so it should be deleted only from filesystem
bool is_duplicate = false;
/// Frozen by ALTER TABLE ... FREEZE ... It is used for information purposes in system.parts table.
mutable std::atomic<bool> is_frozen {false};
/**
* Part state is a stage of its lifetime. States are ordered and state of a part could be increased only.
* Part state should be modified under data_parts mutex.
*
* Possible state transitions:
* Temporary -> Precommitted: we are trying to commit a fetched, inserted or merged part to active set
* Precommitted -> Outdated: we could not to add a part to active set and doing a rollback (for example it is duplicated part)
* Precommitted -> Commited: we successfully committed a part to active dataset
* Precommitted -> Outdated: a part was replaced by a covering part or DROP PARTITION
* Outdated -> Deleting: a cleaner selected this part for deletion
* Deleting -> Outdated: if an ZooKeeper error occurred during the deletion, we will retry deletion
* Committed -> DeleteOnDestroy if part was moved to another disk
*/
enum class State
{
Temporary, /// the part is generating now, it is not in data_parts list
PreCommitted, /// the part is in data_parts, but not used for SELECTs
Committed, /// active data part, used by current and upcoming SELECTs
Outdated, /// not active data part, but could be used by only current SELECTs, could be deleted after SELECTs finishes
Deleting, /// not active data part with identity refcounter, it is deleting right now by a cleaner
DeleteOnDestroy, /// part was moved to another disk and should be deleted in own destructor
};
using TTLInfo = MergeTreeDataPartTTLInfo;
using TTLInfos = MergeTreeDataPartTTLInfos;
TTLInfos ttl_infos;
/// Current state of the part. If the part is in working set already, it should be accessed via data_parts mutex
mutable State state{State::Temporary};
/// Returns name of state
static String stateToString(State state);
String stateString() const;
String getNameWithState() const
{
return name + " (state " + stateString() + ")";
}
/// Returns true if state of part is one of affordable_states
bool checkState(const std::initializer_list<State> & affordable_states) const
{
for (auto affordable_state : affordable_states)
{
if (state == affordable_state)
return true;
}
return false;
}
/// Throws an exception if state of the part is not in affordable_states
void assertState(const std::initializer_list<State> & affordable_states) const;
/// Primary key (correspond to primary.idx file).
/// Always loaded in RAM. Contains each index_granularity-th value of primary key tuple.
/// Note that marks (also correspond to primary key) is not always in RAM, but cached. See MarkCache.h.
using Index = Columns;
Index index;
MergeTreePartition partition;
/// Amount of rows between marks
/// As index always loaded into memory
MergeTreeIndexGranularity index_granularity;
/// Index that for each part stores min and max values of a set of columns. This allows quickly excluding
/// parts based on conditions on these columns imposed by a query.
/// Currently this index is built using only columns required by partition expression, but in principle it
/// can be built using any set of columns.
struct MinMaxIndex
{
/// A direct product of ranges for each key column. See Storages/MergeTree/KeyCondition.cpp for details.
std::vector<Range> parallelogram;
bool initialized = false;
public:
MinMaxIndex() = default;
/// For month-based partitioning.
MinMaxIndex(DayNum min_date, DayNum max_date)
: parallelogram(1, Range(min_date, true, max_date, true))
, initialized(true)
{
}
void load(const MergeTreeData & storage, const String & part_path);
void store(const MergeTreeData & storage, const String & part_path, Checksums & checksums) const;
void store(const Names & column_names, const DataTypes & data_types, const String & part_path, Checksums & checksums) const;
void update(const Block & block, const Names & column_names);
void merge(const MinMaxIndex & other);
};
MinMaxIndex minmax_idx;
Checksums checksums;
/// Columns description.
NamesAndTypesList columns;
/// Columns with values, that all have been zeroed by expired ttl
NameSet expired_columns;
/** It is blocked for writing when changing columns, checksums or any part files.
* Locked to read when reading columns, checksums or any part files.
*/
mutable std::shared_mutex columns_lock;
/** It is taken for the whole time ALTER a part: from the beginning of the recording of the temporary files to their renaming to permanent.
* It is taken with unlocked `columns_lock`.
*
* NOTE: "You can" do without this mutex if you could turn ReadRWLock into WriteRWLock without removing the lock.
* This transformation is impossible, because it would create a deadlock, if you do it from two threads at once.
* Taking this mutex means that we want to lock columns_lock on read with intention then, not
* unblocking, block it for writing.
*/
mutable std::mutex alter_mutex;
ColumnSizeByName columns_sizes;
/// For data in RAM ('index')
UInt64 getIndexSizeInBytes() const;
UInt64 getIndexSizeInAllocatedBytes() const;
UInt64 getMarksCount() const;
size_t getFileSizeOrZero(const String & file_name) const;
String getFullPath() const;
void renameTo(const String & new_relative_path, bool remove_new_dir_if_exists = false) const;
void renameToDetached(const String & prefix) const;
void makeCloneInDetached(const String & prefix) const;
void makeCloneOnDiskDetached(const DiskSpace::ReservationPtr & reservation) const;
/// Checks that .bin and .mrk files exist
virtual bool hasColumnFiles(const String & /* column */, const IDataType & /* type */ ) const { return true; }
static UInt64 calculateTotalSizeOnDisk(const String & from);
protected:
void removeIfNeeded();
virtual void checkConsistency(bool require_part_metadata) const;
private:
Block sample_block;
/// Reads columns names and types from columns.txt
void loadColumns(bool require);
/// If checksums.txt exists, reads files' checksums (and sizes) from it
void loadChecksums(bool require);
/// Loads marks index granularity into memory
virtual void loadIndexGranularity();
/// Loads index file.
void loadIndex();
/// Load rows count for this part from disk (for the newer storage format version).
/// For the older format version calculates rows count from the size of a column with a fixed size.
void loadRowsCount();
/// Loads ttl infos in json format from file ttl.txt. If file doesn`t exists assigns ttl infos with all zeros
void loadTTLInfos();
void loadPartitionAndMinMaxIndex();
void loadColumnSizes();
String getRelativePathForDetachedPart(const String & prefix) const;
};
using MergeTreeDataPartState = IMergeTreeDataPart::State;
using MergeTreeDataPartPtr = std::shared_ptr<const IMergeTreeDataPart>;
}