Tuning parameters for the database. More...
#include <tkrzw_dbm_tree.h>
Public Member Functions | |
| TuningParameters () | |
| Constructor. More... | |
 Public Member Functions inherited from tkrzw::HashDBM::TuningParameters | |
| TuningParameters () | |
| Constructor. More... | |
Public Attributes | |
| int32_t | max_page_size = -1 |
| The maximum size of a page. More... | |
| int32_t | max_branches = -1 |
| The maximum number of branches each inner node can have. More... | |
| int32_t | max_cached_pages = -1 |
| The maximum number of cached pages. More... | |
| PageUpdateMode | page_update_mode = PAGE_UPDATE_DEFAULT |
| What to do when each page is updated. More... | |
| KeyComparator | key_comparator = nullptr |
| The comparator of record keys. More... | |
| Public Attributes inherited from tkrzw::HashDBM::TuningParameters | |
| UpdateMode | update_mode = UPDATE_DEFAULT |
| How to update the database file. More... | |
| RecordCRCMode | record_crc_mode = RECORD_CRC_DEFAULT |
| How to add the CRC data to the record. More... | |
| RecordCompressionMode | record_comp_mode = RECORD_COMP_DEFAULT |
| How to compress the value data of the record. More... | |
| int32_t | offset_width = -1 |
| The width to represent the offset of records. More... | |
| int32_t | align_pow = -1 |
| The power to align records. More... | |
| int64_t | num_buckets = -1 |
| The number of buckets for hashing. More... | |
| int32_t | restore_mode = RESTORE_DEFAULT |
| How to restore the broken database file. More... | |
| int32_t | fbp_capacity = -1 |
| The capacity of the free block pool. More... | |
| int32_t | min_read_size = -1 |
| The minimum reading size to read a record. More... | |
| int32_t | cache_buckets = -1 |
| Whether to cache the hash buckets on memory. More... | |
| std::string | cipher_key = "" |
| The encryption key for cipher compressors. More... | |
Detailed Description
Tuning parameters for the database.
Constructor & Destructor Documentation
◆ TuningParameters()
| tkrzw::TreeDBM::TuningParameters::TuningParameters | ( | ) |
Constructor.
Member Data Documentation
◆ max_page_size
| int32_t tkrzw::TreeDBM::TuningParameters::max_page_size = -1 |
The maximum size of a page.
If the size of a page exceeds this value, the page is divided into two. -1 means that the default value 4081 is set. -1 means that the default value 8130 is set.
◆ max_branches
| int32_t tkrzw::TreeDBM::TuningParameters::max_branches = -1 |
The maximum number of branches each inner node can have.
The more the number of branches is, the less number of inner nodes occur. If the number is too large, updating performance deteriorates. -1 means that the default value 256 is set.
◆ max_cached_pages
| int32_t tkrzw::TreeDBM::TuningParameters::max_cached_pages = -1 |
The maximum number of cached pages.
The more this value is, the better performance is whereas memory usage is increased. -1 means that the default value 10000 is set. As this parameter is not saved as a metadata of the database, it should be set each time when opening the database.
◆ page_update_mode
| PageUpdateMode tkrzw::TreeDBM::TuningParameters::page_update_mode = PAGE_UPDATE_DEFAULT |
What to do when each page is updated.
By default, updated cached pages are just kept on memory and the updates of each page are not written in the file until the page is cached out or the database is closed. PAGE_UPDATE_WRITE improves durability by ensuring that each update is written immediately.
◆ key_comparator
| KeyComparator tkrzw::TreeDBM::TuningParameters::key_comparator = nullptr |
The comparator of record keys.
Records are put in the ascending order of this function. If this is one of built-in comparators, the type is stored in the database. Otherwise, the custom comparator must be specified every time when the database is opened. nullptr means that the default comparator LexicalKeyComparator is set.
