Windows: Virtual bytes considerably larger than SGA+PGA?

Hey all,

  I have a 9206 enterprise database running on windows 2003 standard with the 3GB switch. My SGA is 1200M and my PGA target is 300M, currently the maximum pga allocated (v$pgastat) is 380M. So, if I add those values up, my oracle instance should be consuming about 1580MB of memory.

However, if I startup perfmon and look at the virtual bytes for the oracle process its 2666MB. At about 3000MB we hit the windows limit and start getting memory errors. (I know the theoretic max is about 3.2GB but in reality you don't get that much do to memory fragmentation..)

My question is, if my instance is only using 1580MB of ram, why is my virtual bytes at 2666MB? Where is the extra 1GB coming from? What am I missing?

tnx. Received on Tue Jan 10 2006 - 10:13:18 CST