Can Dbc::get() with DB_NEXT for DB_RECNO db as fast as DB_BTREE db?

Question

My application stores all the user information in the data field and keeps an id for the record in the key field. In one scenario, the database is created as DB_BTREE, and in another, DB_RECNO is used. In both scenarios, the ids are 1-based and continuous, but in the DB_RECNO database, the rids can be changed.
Now, I am implementing an operation. That is, given a set of ids, find relevant records in the database. The id set is provided in ascending order and is so large that scanning the whole database and checking the key is faster than retrieving the records directly by the key.
The problem is like this. When using DB_BTREE, if I use Dbc::get() with DB_NEXT flag and check the key, the speed is two times faster than using Dbc::get() with DB_SET. I think this is because when searching with keys, BDB has to visit the internal nodes, which is not necessary if DB_NEXT is used. However, when using DB_RECNO, the speeds are almost the same for the two methods. Does this mean that for DB_RECNO databases, internal nodes have to be visited even to get the next record? Is there any method that can scan a DB_RECNO database as fast as scan a DB_BTREE database?

Answer 1

Hello,
I'm looking into this now.
Thanks,
Sandra