#include <db_cxx.h> int Db::set_h_nelem(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 either returns a non-zero error value or throws an
exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
The Db::set_h_nelem()
method may fail and throw a DbException
exception, encapsulating one of the following non-zero errors, or return one
of the following non-zero errors:
If the method was called after Db::open() was called; or if an invalid flag value or parameter was specified.