Printable View
I increased the buffer size by 50% to 12888.
When there were a couple of users the hit ratio was 96%.
Now it has gone down to 60-705 as more users have logged on. Is this normal ?
I am planning on re-building the indexes over the weekend. will this help ?
quote:
---------------------------------------------
Originally posted by julian:
In Oracle 7 that used to be the best possible ratio.
In Oracle 8 and 9 SGA can be half of the OS memory.
-----------------------------------------------------
For as long as all Oracle Processes don't utilize swap file
then fine I agree on that. But try to consider other memory utilization used by oracle such as sort_area_size.
Let me make an example, correct me If I am wrong, In a DSS/DW system let's say 10 concurrent user all together generate a report, it utilizes 10 times of the sort_area_size because a value of sort_area_size was allocate to each user and you know how large value should have for sort_area_size with this kind of setup. This is one aspect of memory utilization that is usually overlooked.
------------------------------------------------------
The goal for the future is to get the complete DB in memory!
---------------------------------------------
I don't know, for me this can only be a wishful thinking for the next 5-10 years.
Keep it cool.
You will have to monitor it over a day or two, at the start the buffers will be empty and therefore the cache hit ratio will suffer.
You are aboslutely right. These are just basic headlines. One should take into account sort_area_size.
1-2 years!Quote:
I don't know, for me this can only be a wishful thinking for the next 5-10 years.Keep it cool.