Berkeley DB

Retrieving Btree Records by Number

The Btree access method optionally supports retrieval by logical record numbers. To configure a Btree to support record numbers, call the DB→set_flags function with the DB_RECNUM flag.

Configuring a Btree for record numbers should not be done lightly. Although often useful, it requires that storing items into the database be single-threaded, which can severely impact application throughput. Generally, it should be avoided in trees with a need for high write concurrency.

To determine a key’s record number, use the DB_GET_RECNO flag to the DBcursor→c_get function.To retrieve by record number, use the DB_SET_RECNO flag to the DB→get and DBcursor→c_get functions.