H5P_SET_ATTR_PHASE_CHANGE
Sets attribute storage phase change thresholds
Procedure:
H5P_SET_ATTR_PHASE_CHANGE ( ocpl_id, max_compact, min_dense )
Signature:
herr_t H5Pset_attr_phase_change(
hid_t ocpl_id,
unsigned max_compact,
unsigned min_dense
)
Fortran90 Interface: h5pset_attr_phase_change_f
SUBROUTINE h5pset_attr_phase_change_f(ocpl_id, max_compact, min_dense, hdferr)
IMPLICIT NONE
INTEGER(HID_T), INTENT(IN) :: ocpl_id
! Object (dataset or group) creation property
! list identifier
INTEGER, INTENT(IN) :: max_compact
! Maximum number of attributes to be stored in
! compact storage (Default: 8)
INTEGER, INTENT(IN) :: min_dense
! Minimum number of attributes to be stored in
! dense storage (Default: 6)
INTEGER, INTENT(OUT) :: hdferr
! Error code
! 0 on success and -1 on failure
END SUBROUTINE h5pset_attr_phase_change_f
Parameters:
hid_t ocpl_id | IN: Object (group or dataset) creation property list identifier |
unsigned max_compact | IN: Maximum number of attributes to be stored in compact storage (Default: 8); must be greater than or equal to min_dense
|
unsigned min_dense | IN: Minimum number of attributes to be stored in dense storage (Default: 6) |
Description:
H5P_SET_ATTR_PHASE_CHANGE sets threshold values for attribute storage on an object. These thresholds determine the point at which attribute storage changes from compact storage (i.e., storage in the object header) to dense storage (i.e., storage in a heap and indexed with a B-tree).
In the general case, attributes are initially kept in compact storage. When the number of attributes exceeds max_compact, attribute storage switches to dense storage. If the number of attributes subsequently falls below min_dense, the attributes are returned to compact storage.
If max_compact is set to 0 (zero), dense storage is always used. min_dense must be set to 0 (zero) when max_compact is 0 (zero).
ocpl_id is a dataset or group creation property list identifier. The term ocpl, for object creation property list, is used when different types of objects may be involved.
Returns:
Returns a non-negative value if successful; otherwise returns a negative value.
Example:
History:
| Release | Change |
|---|
| 1.8.0 | Function introduced in this release. |
--- Last Modified: July 14, 2020 | 09:55 AM
