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Home -> Community -> Usenet -> c.d.o.server -> Re: What does "koh-kghu call " mean?
"Connor McDonald" <connor_mcdonald_at_yahoo.com> wrote in message
news:442681C3.6D75_at_yahoo.com...
> Jonathan Lewis wrote:
>>
>> In the SGA management, there are 255 lists, of which the
>> first 200 or so are each for a very specific chunk size
>> (changine by four bytes as you go from list to list) then
>> about 50 with size ranges. This lets Oracle find free memory
>> very rapidly for SGA management - possibly the same code
>> has been applied for the PGA with fewer items in the list,
>> therefore a greater need to standard the use of chunk sizes
>> and minimize the possible chunk count. One strategy for
>> this would be to 'predict' the need for large chunks than
>> the actual code call demanded. If you change my test from
>> 4K strings to 16K strings, I think the allocation jumped to
>> chunks of 64K.
>>
>
> Can't remember where I read it, and certainly haven't tried to verify
> it, but from 10.2, the 255 lists apparently have been raised to 4096.
>
Just did a quick check.
It hasn't changed from 255, but the free memory for the reserved pool has been split from a single free list to a set of 14 free lists with the following lower limits:
Reserved bucket 0 size=16 Reserved bucket 1 size=4400 Reserved bucket 2 size=8204 Reserved bucket 3 size=8460 Reserved bucket 4 size=8464 Reserved bucket 5 size=8468 Reserved bucket 6 size=8472 Reserved bucket 7 size=9296 Reserved bucket 8 size=9300 Reserved bucket 9 size=12320 Reserved bucket 10 size=12324 Reserved bucket 11 size=16396
I believe there was a paper at Oracle World this year that said that they were trying to increase the use of standard size chunks of 1K and 4K in the shared pool. Perhaps that's where your memory of 4096 cam from.
-- Regards Jonathan Lewis http://www.oracle.com/technology/community/oracle_ace/ace1.html#lewis The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html Cost Based Oracle: Fundamentals http://www.jlcomp.demon.co.uk/cbo_book/ind_book.htmlReceived on Mon Mar 27 2006 - 02:02:18 CST
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