int DB_ENV->set_flags(DB_ENV *dbenv, u_int32_t flags, int onoff);
The flags value must be set to 0 or by bitwise inclusively OR'ing together one or more of the following values: If onoff is set to zero, the specified flags are cleared; otherwise they are set.
The number of transactions potentially at risk is governed by how often the log is checkpointed (see db_checkpoint for more information) and how many log updates can fit into the log buffer.
The DB_ENV->set_flags function returns a non-zero error value on failure and 0 on success.
The database environment's flag values may also be set using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_flags", one or more whitespace characters, and the interface flag argument as a string; for example, "set_flags DB_TXN_NOSYNC". Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.
The DB_ENV->set_flags function may fail and return a non-zero error for the following conditions:
The DB_ENV->set_flags function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DB_ENV->set_flags function may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.
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