Set the size of the pages used to hold items in the database, in bytes.
The minimum page size is 512 bytes and the maximum page size is 64K bytes.
If the page size is not explicitly set, one is selected based on the
underlying filesystem I/O block size. The automatically selected size
has a lower limit of 512 bytes and an upper limit of 16K bytes.
The Db::set_pagesize interface may only be used to configure Berkeley DB before
the Db::open interface is called.
The Db::set_pagesize 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.