Re: SGA_MAX_SIZE vs. SGA_TARGET

From: Andrew Kerber <andrew.kerber_at_gmail.com>
Date: Sat, 5 Sep 2015 13:12:54 -0500
Message-Id: <43F29D84-2525-4912-BD46-764D68CF7067_at_gmail.com>

As I recall on Solaris it has something to do with how it uses intimate shared memory (ism).

Sent from my iPad

> On Sep 5, 2015, at 1:07 PM, Dba DBA <oracledbaquestions_at_gmail.com> wrote:
>
> Was really getting worried I was senile and was going to start drooling on myself. I knew I was able to get memory to allocate and deallocate in the past. It was on Solaris.
>
> Does anyone know why this varies by unix/linux flavor? What is solaris doing that Linux does not?
>

>> On Sat, Sep 5, 2015 at 1:54 PM, Neil Chandler <neil_chandler_at_hotmail.com> wrote:
>> It depends upon your platform. Most platforms allocate max_size so having a lower sga_target is pointless and a waste of memory. Some platforms do not (Solaris), and only allocate sga_target, with max_size an unused top limit.
>> 
>> Neil.
>> sent from my phone
>> 
>> > On 5 Sep 2015, at 18:51, Dba DBA <oracledbaquestions_at_gmail.com> wrote:
>> >
>> > yeah this is old. I know its on the web. However, the responses I see are not to the question I have.
>> >
>> > What is the point to having two parameters? If SGA_MAX_SIZE reserves memory for oracle as an upper bound, but would I want to be able to raise and lower SGA_TARGET? What do I do with the 'spare memory'. PGA_AGGREGATE_TARGET is separate and not taken from memory reserved with SGA_MAX_SIZE
>> >
>> > db_cache,shared_pool, large_pool,streams, java, etc... all come out of SGA_TARGET. So what is the point to this? I am missing something.
>> >
>> > I have I have 20 GB SGA_MAX_SIZE and a 10 GB SGA_TARGET. What is oracle doing with the other 10 GB?
>> >

>

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Received on Sat Sep 05 2015 - 20:12:54 CEST