Oracle 10gR2 LARGE PAGE SIZE on Windows 2008 x64 SP2
767404Apr 17 2010 — edited Apr 18 2010Hello Oracle Experts,
What are the advantages of Large Page Size and how would I know when my DB will benefit from Large Page Sizes?
My undeqrstanding is on Windows x64 – 8kb default page size – will now be 2 MB. Will this speed up accesses to buffer cache? If so is there a latch wait that I can monitor before vs. after to verify that large page size has improved performance?
My Database server has 256GB RAM and SGA is set to 180GB. I am quite sure the overhead involved in maintaining a large number of 8kb allocations (as opposed to 2MB) must be high - how can i monitor this?
I am planning to follow the procedure here:
http://download.oracle.com/docs/html/B13831_01/ap_64bit.htm#CHDGFJJD
The DB is for SAP on a 8CPU/48 core IBM x3950. For some reason SAP documentation does not mention anything about this registry setting or even if Large Page Size is supported in the SAP world.
Part 2 : I notice that more recent Oracle patch sets (example 25) turn NUMA OFF by default. Why is this and what is the impact of disabling NUMA on a system like x3950 (which is a NUMA based server)?
My understanding is Oracle would no longer know that some memory is Local (and therefore fast) and some memory is Remote (therefore slow). Overall I am guessing this could cause a real performance issue on this DB.
-points for detailed reply!
thanks a lot -