Chapter 25. Dumping and Reloading Databases

The db_dump and db_load utilities

There are three utilities used for dumping and loading Berkeley DB databases: the db_dump utility, the db_dump185 utility and the db_load utility.

The db_dump utility and the db_dump185 utility dump Berkeley DB databases into a flat-text representation of the data that can be read by db_load utility. The only difference between them is that the db_dump utility reads Berkeley DB version 2 and greater database formats, whereas the db_dump185 utility reads Berkeley DB version 1.85 and 1.86 database formats.

The db_load utility reads either the output format used by the dump utilities or (optionally) a flat-text representation created using other tools, and stores it into a Berkeley DB database.

Dumping and reloading Hash databases that use user-defined hash functions will result in new databases that use the default hash function. Although using the default hash function may not be optimal for the new database, it will continue to work correctly.

Dumping and reloading Btree databases that use user-defined prefix or comparison functions will result in new databases that use the default prefix and comparison functions. In this case, it is quite likely that applications will be unable to retrieve records, and it is possible that the load process itself will fail.

The only available workaround for either Hash or Btree databases is to modify the sources for the db_load utility to load the database using the correct hash, prefix, and comparison functions.