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rocksdb/include/rocksdb/table_properties.h

199 lines
7.4 KiB

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <stdint.h>
#include <string>
#include <map>
#include "rocksdb/status.h"
#include "rocksdb/types.h"
namespace rocksdb {
// -- Table Properties
// Other than basic table properties, each table may also have the user
// collected properties.
// The value of the user-collected properties are encoded as raw bytes --
// users have to interprete these values by themselves.
// Note: To do prefix seek/scan in `UserCollectedProperties`, you can do
// something similar to:
//
// UserCollectedProperties props = ...;
// for (auto pos = props.lower_bound(prefix);
// pos != props.end() && pos->first.compare(0, prefix.size(), prefix) == 0;
// ++pos) {
// ...
// }
typedef std::map<std::string, std::string> UserCollectedProperties;
// table properties' human-readable names in the property block.
struct TablePropertiesNames {
static const std::string kDataSize;
static const std::string kIndexSize;
static const std::string kFilterSize;
static const std::string kRawKeySize;
static const std::string kRawValueSize;
static const std::string kNumDataBlocks;
static const std::string kNumEntries;
static const std::string kFormatVersion;
static const std::string kFixedKeyLen;
static const std::string kFilterPolicy;
static const std::string kColumnFamilyName;
static const std::string kColumnFamilyId;
static const std::string kComparator;
static const std::string kMergeOperator;
static const std::string kPropertyCollectors;
static const std::string kCompression;
};
extern const std::string kPropertiesBlock;
extern const std::string kCompressionDictBlock;
enum EntryType {
kEntryPut,
kEntryDelete,
kEntrySingleDelete,
kEntryMerge,
kEntryOther,
};
// `TablePropertiesCollector` provides the mechanism for users to collect
// their own properties that they are interested in. This class is essentially
// a collection of callback functions that will be invoked during table
// building. It is construced with TablePropertiesCollectorFactory. The methods
// don't need to be thread-safe, as we will create exactly one
// TablePropertiesCollector object per table and then call it sequentially
class TablePropertiesCollector {
public:
virtual ~TablePropertiesCollector() {}
// DEPRECATE User defined collector should implement AddUserKey(), though
// this old function still works for backward compatible reason.
// Add() will be called when a new key/value pair is inserted into the table.
// @params key the user key that is inserted into the table.
// @params value the value that is inserted into the table.
virtual Status Add(const Slice& /*key*/, const Slice& /*value*/) {
return Status::InvalidArgument(
"TablePropertiesCollector::Add() deprecated.");
}
// AddUserKey() will be called when a new key/value pair is inserted into the
// table.
// @params key the user key that is inserted into the table.
// @params value the value that is inserted into the table.
virtual Status AddUserKey(const Slice& key, const Slice& value,
EntryType /*type*/, SequenceNumber /*seq*/,
uint64_t /*file_size*/) {
// For backwards-compatibility.
return Add(key, value);
}
// Finish() will be called when a table has already been built and is ready
// for writing the properties block.
// @params properties User will add their collected statistics to
// `properties`.
virtual Status Finish(UserCollectedProperties* properties) = 0;
// Return the human-readable properties, where the key is property name and
// the value is the human-readable form of value.
virtual UserCollectedProperties GetReadableProperties() const = 0;
// The name of the properties collector can be used for debugging purpose.
virtual const char* Name() const = 0;
// EXPERIMENTAL Return whether the output file should be further compacted
virtual bool NeedCompact() const { return false; }
};
// Constructs TablePropertiesCollector. Internals create a new
// TablePropertiesCollector for each new table
class TablePropertiesCollectorFactory {
public:
struct Context {
uint32_t column_family_id;
static const uint32_t kUnknownColumnFamily;
};
virtual ~TablePropertiesCollectorFactory() {}
// has to be thread-safe
virtual TablePropertiesCollector* CreateTablePropertiesCollector(
TablePropertiesCollectorFactory::Context context) = 0;
// The name of the properties collector can be used for debugging purpose.
virtual const char* Name() const = 0;
};
// TableProperties contains a bunch of read-only properties of its associated
// table.
struct TableProperties {
public:
// the total size of all data blocks.
uint64_t data_size = 0;
// the size of index block.
uint64_t index_size = 0;
// the size of filter block.
uint64_t filter_size = 0;
// total raw key size
uint64_t raw_key_size = 0;
// total raw value size
uint64_t raw_value_size = 0;
// the number of blocks in this table
uint64_t num_data_blocks = 0;
// the number of entries in this table
uint64_t num_entries = 0;
// format version, reserved for backward compatibility
uint64_t format_version = 0;
// If 0, key is variable length. Otherwise number of bytes for each key.
uint64_t fixed_key_len = 0;
// ID of column family for this SST file, corresponding to the CF identified
// by column_family_name.
uint64_t column_family_id =
rocksdb::TablePropertiesCollectorFactory::Context::kUnknownColumnFamily;
// Name of the column family with which this SST file is associated.
// If column family is unknown, `column_family_name` will be an empty string.
std::string column_family_name;
// The name of the filter policy used in this table.
// If no filter policy is used, `filter_policy_name` will be an empty string.
std::string filter_policy_name;
// The name of the comparator used in this table.
std::string comparator_name;
// The name of the merge operator used in this table.
// If no merge operator is used, `merge_operator_name` will be "nullptr".
std::string merge_operator_name;
// The names of the property collectors factories used in this table
// separated by commas
// {collector_name[1]},{collector_name[2]},{collector_name[3]} ..
std::string property_collectors_names;
// The compression algo used to compress the SST files.
std::string compression_name;
// user collected properties
UserCollectedProperties user_collected_properties;
UserCollectedProperties readable_properties;
// convert this object to a human readable form
// @prop_delim: delimiter for each property.
std::string ToString(const std::string& prop_delim = "; ",
const std::string& kv_delim = "=") const;
// Aggregate the numerical member variables of the specified
// TableProperties.
void Add(const TableProperties& tp);
};
// Extra properties
// Below is a list of non-basic properties that are collected by database
// itself. Especially some properties regarding to the internal keys (which
// is unknown to `table`).
extern uint64_t GetDeletedKeys(const UserCollectedProperties& props);
extern uint64_t GetMergeOperands(const UserCollectedProperties& props,
bool* property_present);
} // namespace rocksdb