DB->set_h_nelem()
#include <db.h>
int
DB->set_h_nelem(DB *db, u_int32_t h_nelem); Set an estimate of the final size of the hash table.
In order for the estimate to be used when creating the database, the DB->set_h_ffactor() method must also be called. If the estimate or fill factor are not set or are set too low, hash tables will still expand gracefully as keys are entered, although a slight performance degradation may be noticed.
The DB->set_h_nelem() method configures a database, not only operations performed using the specified DB handle.
The DB->set_h_nelem() method may not be called after the DB->open() method is called. If the database already exists when DB->open() is called, the information specified to DB->set_h_nelem() will be ignored.
The DB->set_h_nelem() method returns a non-zero error value on failure and 0 on success.
Parameters
h_nelem
The h_nelem parameter is an estimate of the final size of the hash table.
Errors
The DB->set_h_nelem() method may fail and return one of the following non-zero errors:
EINVAL
If the method was called after DB->open() was called; or if an invalid flag value or parameter was specified.