data buffer access confusion

  • From: Aman Sharma <amansharma1981@xxxxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Sat, 21 Aug 2010 01:33:22 +0530

Hi List,

Is it a correct thing to say that when the data buffer is being read from
the disk, its first kept in the PGA and then later on, it would be copied
from the PGA memory to the standard buffer cache? If no, then its alright
but if yes, why such behavior is there? If we say that the buffer handle is
kept there in the PGA, its still somewhat reasonable since there won't take
much of the memory to keep just a buffer handle but I believe to keep a full
buffer, there would be a lot of PGA memory needed and furthermore, copying
from the PGA to the buffer cache would also be a resource and time consuming
operation IMO. If anyone can explain and clear this confusion, it would be
just great!

Thanks in advance.

Aman Sharma

Other related posts: