Tkrzw
Public Member Functions | Public Attributes | List of all members
tkrzw::SkipDBM::TuningParameters Struct Reference

Tuning parameters for the database. More...

#include <tkrzw_dbm_skip.h>

Public Member Functions

 TuningParameters ()
 Constructor. More...
 

Public Attributes

int32_t offset_width = -1
 The width to represent the offset of records. More...
 
int32_t step_unit = -1
 The step unit of the skip list. More...
 
int32_t max_level = -1
 The maximum level of the skip list. More...
 
int64_t sort_mem_size = -1
 The memory size used for sorting to build the database in the at-random mode. More...
 
bool insert_in_order = false
 If true, records are assumed to be inserted in ascending order of the key. More...
 
int32_t max_cached_records = -1
 The maximum number of cached records. More...
 

Detailed Description

Tuning parameters for the database.

Constructor & Destructor Documentation

◆ TuningParameters()

tkrzw::SkipDBM::TuningParameters::TuningParameters ( )

Constructor.

Member Data Documentation

◆ offset_width

int32_t tkrzw::SkipDBM::TuningParameters::offset_width = -1

The width to represent the offset of records.

This determines the maximum size of the database and the footprint. -1 means that the default value 4 is set.

◆ step_unit

int32_t tkrzw::SkipDBM::TuningParameters::step_unit = -1

The step unit of the skip list.

This determines the search speed and the footprint of records. -1 means that the default value 4 is set.

◆ max_level

int32_t tkrzw::SkipDBM::TuningParameters::max_level = -1

The maximum level of the skip list.

This determines the search speed and the footprint of records. -1 means that the default value 14 is set.

◆ sort_mem_size

int64_t tkrzw::SkipDBM::TuningParameters::sort_mem_size = -1

The memory size used for sorting to build the database in the at-random mode.

When total size of records exceeds this value, records are written in a temporary file and they are merged later. -1 means that the default value 256MB is set. As this parameter is not saved as a metadata of the database, it should be set each time when opening the database.

◆ insert_in_order

bool tkrzw::SkipDBM::TuningParameters::insert_in_order = false

If true, records are assumed to be inserted in ascending order of the key.

This assumption makes the insertions effective. As this parameter is not saved as a metadata of the database, it should be set each time when opening the database.

◆ max_cached_records

int32_t tkrzw::SkipDBM::TuningParameters::max_cached_records = -1

The maximum number of cached records.

The more this value is, the better performance is whereas memory usage is increased. -1 means that the default value 65536 is set. As this parameter is not saved as a metadata of the database, it should be set each time when opening the database.