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Disk-Related Parameters

The following are disk-related parameters for defining database volumes and storing files. The type and value range for each parameter are as follows:

Parameter Name

Type

Default Value

Min.

Max.

db_volume_size

int

512M

20M

20G

dont_reuse_heap_file

bool

no

 

 

log_volume_size

int

512M

20M

4G

temp_file_max_size_in_pages

int

-1

 

 

temp_volume_path

string

NULL

 

 

unfill_factor

float

0.1

0.0

0.3

volume_extension_path

string

NULL

 

 

db_volume_size

A parameter used to specify the following values. The default value is 512M.

  • The default database volume size when cubrid createdb and cubrid addvoldb utility is used without --db-volume-size option.
  • The default size of generic volume that is added automatically when database volume is full.
dont_reuse_heap_file

A parameter used to specify whether or not heap files, which are deleted when deleting the table (DROP TABLE), are to be reused when creating a new table (CREATE TABLE). If this parameter is set to 0, the deleted heap files can be reused; if it is set to 1, the deleted heap files are not used when creating a new table. The default value is 0.

log_volume_size

A parameter used to specify the default size of log volume file when cubrid createdb utility is used without --log-volume-size option. You can set units as K, M, G and T, which stand for kilobytes (KB), megabytes (MB), gigabytes (GB) and terabytes (TB) respectively. If you omit the unit, bytes will be applied. The default value is 512M.

temp_file_max_size_in_pages

A parameter used to specify the maximum number of pages to store temporary volumes in the disk, which are used for the execution of complex queries or sorting; the default value is -1. If this parameter is configured to the default value, unlimited number of temporary temp volumes are created and stored in the directory specified by the temp_volume_path parameter. If it is configured to 0, the administrator must create permanent temp volumes manually by using the cubrid addvoldb utility because temporary temp volumes are not created automatically.

temp_volume_path

A parameter used to specify the directory in which to create temporary temp volumes used for the execution of complex queries or sorting. The default value is the volume location configured during the database creation.

unfill_factor

A parameter used to specify the rate of disk space to be allocated in a heap page for data updates. The default value is 0.1. That is, the rate of free space is configured to 10%. In principle, data in the table is inserted in physical order. However, if the size of the data increases due to updates and there is not enough space for storage in the given page, performance may degrade because updated data must be relocated to another page. To prevent such a problem, you can configure the rate of space for a heap page by using the unfill_factor parameter. The allowable maximum value is 0.3 (30%). In a database where data updates rarely occur, you can configure this parameter to 0.0 so that space will not be allocated in a heap page for data updates. If the value of the unfill_factor parameter is negative or greater than the maximum value, the default value (0.1) is used.

volume_extension_path

A parameter used to specify the directory where automatically extended volumes are to be created. The default value is the volume location configured during the database creation.