About SGA size

From: jeff <xinghj_at_a-1.net.cn>
Date: Fri, 24 Nov 2000 00:17:27 +0800
Message-ID: <8vjgi8$942@gus.buptnet.edu.cn>

I know that SGA contains three parts,Redo log buffer,database buffer cache and shared pool.
So I think the size of the SGA should be the sum of the three parts. I set the corresponding parameters like this:

db_block_buffers                    integer 2048
db_block_size                       integer 8192
log_buffer                          integer 163840
shared_pool_size                    string  15728640

I think the size of SGA should be:

db_block_buffers(2048)*db_block_size(8192)+log_buffer(163840)+shared_pool_si ze(15728640)
=16777216 + 163840 +15728640
=32,666,696

But the result of command SHOW SGA in svrmgrl is: SVRMGR> show sga

Total System Global Area                         35605336 bytes
Fixed Size                                          72536 bytes
Variable Size                                    18583552 bytes
Database Buffers                                 16777216 bytes
Redo Buffers                                       172032 bytes

SVRMGR> Who can help me to explain the difference.Thanks a lot. Received on Thu Nov 23 2000 - 10:17:27 CST