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

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

> 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
>>
>

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