#include <db.h> int DB_ENV->mutex_set_align(DB_ENV *dbenv, u_int32_t align);
Set the mutex alignment, in bytes.
         It is sometimes advantageous to align mutexes on specific byte
         boundaries in order to minimize cache line collisions.   The
         DB_ENV->mutex_set_align() method specifies an alignment for mutexes
         allocated by Berkeley DB.
    
The database environment's mutex alignment 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 "mutex_set_align", one or more whitespace characters, and the mutex alignment 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 DB_ENV->mutex_set_align() method configures a database
         environment, not only operations performed using the specified 
         DB_ENV  handle.
    
         The DB_ENV->mutex_set_align() method may not be called after the
         DB_ENV->open()  method is
         called. If the database environment already exists when 
         DB_ENV->open()  is called, the
         information specified to DB_ENV->mutex_set_align() will be ignored.
    
         The DB_ENV->mutex_set_align() 
            
                  method returns a non-zero error value on failure and 0 on success.
            
            
        
    
                         The DB_ENV->mutex_set_align() 
            
                 method may fail and return one of the following non-zero errors:
            
            
        
                    
If the method was called after DB_ENV->open() was called; or if an invalid flag value or parameter was specified.