PERFORMANCE IMPROVEMENT by mapping WAL FILES

Hi all,         By   mapping  the WAL files by each backend  in to its address
space  using "mmap"  system call , there  will be  bigimprovements  in performance  from the following point of view:
         1.   Each  backend directly writes in to the address
 
space  which is  obtained by  maping  the WAL files.                     this  saves  the write system call at the  end
of
every transaction  which transfres  8k of                     data from user space to kernel.              2.   since
everytransaction does not modify all the 8k
 
content of WAL page , so by issuing the                      fsync , the  kernel  only   transfers only the
kernel pages which are modified , which is  4k for                       linux so fsync time  is saved by  twice.
Any comments ?.


Regards
jana