Berkeley DB Reference Guide: Upgrading Berkeley DB Applications

Release 3.0: the DB_ENV structure

The DB_ENV structure is now opaque for applications in the Berkeley DB 3.0 release. Accesses to any fields within that structure by the application should be replaced with method calls. The following example illustrates this using the historic errpfx structure field. In the Berkeley DB 2.X releases, applications set error prefixes using code similar to the following:

DB_ENV *dbenv;

	dbenv->errpfx = "my prefix";

in the Berkeley DB 3.X releases, this should be done using the DB_ENV->set_errpfx method, as follows:

DB_ENV *dbenv;

	dbenv->set_errpfx(dbenv, "my prefix");

The following table lists the DB_ENV fields previously used by applications and the methods that should now be used to set them.

DB_ENV field	Berkeley DB 3.X method
db_errcall	DB_ENV->set_errcall
db_errfile	DB_ENV->set_errfile
db_errpfx	DB_ENV->set_errpfx
db_lorder	This field was removed from the DB_ENV structure in the Berkeley DB 3.0 release as no application should have ever used it. Any code using it should be evaluated for potential bugs.
db_paniccall	DB_ENV->set_paniccall
db_verbose	DB_ENV->set_verbose Note: the db_verbose field was a simple boolean toggle, the DB_ENV->set_verbose method takes arguments that specify exactly which verbose messages are desired.
lg_max	DB_ENV->set_lg_max
lk_conflicts	DB_ENV->set_lk_conflicts
lk_detect	DB_ENV->set_lk_detect
lk_max	DB_ENV->set_lk_max
lk_modes	DB_ENV->set_lk_conflicts
mp_mmapsize	DB_ENV->set_mp_mmapsize
mp_size	DB_ENV->set_cachesize Note: the DB_ENV->set_cachesize function takes additional arguments. Setting both the second argument (the number of GB in the pool) and the last argument (the number of memory pools to create) to 0 will result in behavior that is backward-compatible with previous Berkeley DB releases.
tx_info	This field was used by applications as an argument to the transaction subsystem functions. As those functions take references to a DB_ENV structure as arguments in the Berkeley DB 3.0 release, it should no longer be used by any application.
tx_max	DB_ENV->set_tx_max
tx_recover	DB_ENV->set_tx_recover

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