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
The Db::set_h_nelem method configures a database, not only operations performed
using the specified Db handle.
The Db::set_h_nelem interface may not be called after the Db::open
interface is called.
If the database already exists when
Db::open is called, the information specified to Db::set_h_nelem will
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 an exception or return a non-zero error for the following conditions:
- An invalid flag value or parameter was specified.
Called after Db::open was called.
The Db::set_h_nelem method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
If a catastrophic error has occurred, the Db::set_h_nelem method may fail and
either return DB_RUNRECOVERY or throw a
in which case all subsequent Berkeley DB calls will fail in the same way.
Databases and Related Methods
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