H5P_SET_SHARED_MESG_PHASE_CHANGE
Sets shared object header message storage phase change thresholds
Procedure:
H5P_SET_SHARED_MESG_PHASE_CHANGE ( fcpl_id, max_list, min_btree )
Signature:
herr_t H5Pset_shared_mesg_phase_change(
hid_t fcpl_id,
unsigned max_list,
unsigned min_btree
)
Parameters:
hid_t fcpl_id | IN: File creation property list identifier |
unsigned max_list | IN: Threshold above which storage of a shared object header message index shifts from list to B-tree |
unsigned min_btree | IN: Threshold below which storage of a shared object header message index reverts to list format |
Description:
H5P_SET_SHARED_MESG_PHASE_CHANGE sets threshold values for storage of shared object header message indexes in a file. These phase change thresholds determine the point at which the index storage mechanism changes from a more compact list format to a more performance-oriented B-tree format, and vice-versa.
By default, a shared object header message index is initially stored as a compact list. When the number of messages in an index exceeds the threshold value of max_list, storage switches to a B-tree for improved performance. If the number of messages subsequently falls below the min_btree threshold, the index will revert to the list format.
If max_list is set to 0 (zero), shared object header message indexes in the file will be created as B-trees and will never revert to lists.
fcpl_id specifies the file creation property list.
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: May 01, 2019 | 03:48 PM
