#include <db_cxx.h> int DbEnv::set_lg_regionmax(u_int32_t lg_regionmax);
Set the size of the underlying logging area of the Berkeley DB environment, in bytes. By default, or if the value is set to 0, the minimum region size is used, approximately 128KB. The log region is used to store filenames, and so may need to be increased in size if a large number of files will be opened and registered with the specified Berkeley DB environment's log manager.
The database environment's log region size may also be configured using the environment's DB_CONFIG file. The syntax of the entry in that file is a single line with the string "set_lg_regionmax", one or more whitespace characters, and the size in bytes. Because the DB_CONFIG file is read when the database environment is opened, it will silently overrule configuration done before that time.
         The DbEnv::set_lg_regionmax() method configures a database
         environment, not only operations performed using the specified 
         DbEnv  handle.
    
         The DbEnv::set_lg_regionmax() method may not be called after the
         DbEnv::open()  method is
         called. If the database environment already exists when 
         DbEnv::open()  is called, the
         information specified to DbEnv::set_lg_regionmax() will be ignored.
    
         The DbEnv::set_lg_regionmax() 
            
            
                method either returns a non-zero error value or throws an
                exception that encapsulates a non-zero error value on
                failure, and returns 0 on success.
            
        
    
                         The DbEnv::set_lg_regionmax() 
            
            
                method may fail and throw a DbException 
                exception, encapsulating one of the following non-zero errors, or return one
                of the following non-zero errors:
            
        
                    
If the method was called after DbEnv::open() was called; or if an invalid flag value or parameter was specified.