Re: Does Oracle PGA take out memory out of SGA?

1 single process can take up all PGA,it depends what is doing, you might hit a bug or memory leak as well. So your dba can be correct

On Wed, Mar 31, 2021, 22:50 Andrew Kerber <andrew.kerber_at_gmail.com> wrote:

> How many processes? how many sessions? Each user session will take up a
> small amount of system memory, so if you have a lot of sessions they might
> be eating up memory.
>
> On Wed, Mar 31, 2021 at 2:47 PM Amit Saroha <eramitsaroha_at_gmail.com>
> wrote:
>
>> Hi All,
>>
>> Below are the settings in my database -
>>
>> NAME TYPE VALUE
>> -------------------- ----------- -----
>> pga_aggregate_target big integer 12G
>> sga_max_size big integer 130G
>> sga_target big integer 0
>> memory_target big integer 0
>> pga_aggregate_limit big integer 0
>>
>> Also, I don't know about MTS, if you can tell me how to check then I can
>> check and share details here.
>>
>>
>> Best Regards,
>> Amit
>>
>>
>> On Wed, Mar 31, 2021 at 3:32 PM Luis Claudio Dias dos Santos <
>> lsantos_at_pobox.com> wrote:
>>
>>> In a nutshell: No.
>>>
>>> PGA is a different pool from SGA. And, more important, SGA has a static
>>> preallocated size. While PGA "size" is always a limit, and is allocated on
>>> demand.
>>>
>>> Parameter pga_aggregate_target defines a somewhat *soft* limit for PGA.
>>> From 12c upwards the parameter pga_aggregate_limit (defaults
>>> to pga_aggregate_target*2) defines the hard limit.
>>>
>>> In some setups using MTS some memory structures normally allocated from
>>> PGA are allocated from SGA. This is comprehensible as, in MTS, there isn't
>>> the 1:1 relation between session and process.
>>>
>>> *--*
>>> *Att*
>>>
>>>
>>> *Luis Santos*
>>>
>>>
>>>
>>> Em qua., 31 de mar. de 2021 às 16:04, Amit Saroha <
>>> eramitsaroha_at_gmail.com> escreveu:
>>>
>>>> Dear All,
>>>>
>>>> Please help me understanding PGA and SGA.
>>>>
>>>> I was under the impression that PGA and Memory and SGA Memory are
>>>> differently allocated. But, in a recent situation, we observed *ORA-7445
>>>> [kghalf] *and my DBA is saying - out of a total of 256 GB system
>>>> memory one session's PGA consumed everything and only 8 MB was left for
>>>> other sessions. But, apart from one process, no other processes were
>>>> impacted so I have doubt that - Oracle consumes SGA memory and Allocates it
>>>> to PGA of a single process.
>>>>
>>>> Please help me understand.
>>>>
>>>>
>>>> Best Regards,
>>>> Amit
>>>>
>>>
>
> --
> Andrew W. Kerber
>
> 'If at first you dont succeed, dont take up skydiving.'
>

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