Library Version 18.1.40

DB->set_h_nelem()
Prev | Chapter 2. The DB Handle | Next

## 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.

### Class

DB

### See Also

Database and Related Methods

Prev | Up | Next
DB->set_h_hash() | Home | DB->set_heapsize()