Re: Increase the size of shared_buffers in AWS RDS 10.11 postgreSQL - Mailing list pgsql-admin



I have verified it already as per the calculation. The current shared buffer is 2.5GB

(2694408/1024/1024).

Which I want to make it 8GB or 24G

How to update this is in AWS like below

SUM({DBInstanceClassMemory/12038},-50003)

On Thu, Jan 28, 2021, 22:37 John Scalia <jayknowsunix@gmail.com> wrote:

Ok, it took a me a bit to locate one of my servers that is the same size as yours.  Now, I did not set this one up, I only inherited it, but it is configured the same as yours, i.e., using that same formula. When I log into it, however, and type: show shared_buffers; it reports 21555264kB. A db.r5.xlarge has 32 GB of memory according to AWS and by my calculations the value for shared_buffers is 20.56GB (21555264/1024/1024) Not quite the 75% value, but this is far greater than the 8GB you’re asking for. So, are you trying to limit it to this lower value, and have you queried yours to see what the shared_buffers is set to?

Sent from my iPad

On Jan 28, 2021, at 11:30 AM, dbatoCloud Solution <dbatocloud17@gmail.com> wrote:



Hi,

Ok Sure. But in the parameter group , i can see  like this SUM({DBInstanceClassMemory/12038},-50003)  . How to calculate it ? where should I update it . Should I do change it in 12038 value.

What is meant by DBInstanceClassMemory? My RDS instance shape is "db.r5.xlarge". I am confused with this parameter?

Can you please help me?

 

Thanks & Best Wishes,

Ashok

 

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Ashokkumar Mani  (OCP12c/11g/10g/9i, AWS SAA, M103)

Dubai , UAE | BLR , INDIA

M: +971 54 723 0075 | +91 90086 70302 | WApp : +91 81975 99922

W: https://dbatocloudsolution.blogspot.in/ | E: dbatocloud17@gmail.com

On Thu, Jan 28, 2021 at 9:44 PM John Scalia <jayknowsunix@gmail.com> wrote:

Well, you should understand the AWS recommends a 75% setting, or 24GB in their documentation. So, why don’t you just set the value as something like that in your database parameter group settings.

Sent from my iPad

On Jan 28, 2021, at 10:55 AM, dbatoCloud Solution <dbatocloud17@gmail.com> wrote:



Hi John,

Yes, I calculated as per pgtune(https://pgtune.leopard.in.ua/#/)

 advisor. I took 25% of physical memory 32GB in AWS RDS PostgreSQL which is 8GB. 

AWS PostgreSQL Configuration: -

<image.png>

 

<image.png>

How to update the shared_buffer into 8GB in the AWS RDS Parameter Group here below?

<image.png>

Thanks & Best Wishes,

Ashok

 

---------------------------------------------------------------------------------------------------------------------

Ashokkumar Mani  (OCP12c/11g/10g/9i, AWS SAA, M103)

Dubai , UAE | BLR , INDIA

M: +971 54 723 0075 | +91 90086 70302 | WApp : +91 81975 99922

W: https://dbatocloudsolution.blogspot.in/ | E: dbatocloud17@gmail.com

On Thu, Jan 28, 2021 at 6:05 PM dbatoCloud Solution <dbatocloud17@gmail.com> wrote:

Hi All,

I want to increase the size of shared_buffers in AWS RDS postgreSQL 10.11.  When I see it in the DB parameter group in AWS it says "SUM({DBInstanceClassMemory/12038},-50003)"  and at the instance level I see 2694408 .

Please let  me know how to calculate and  change the value for 8GB?

 

 

Thanks & Best Wishes,

Ashok

 

---------------------------------------------------------------------------------------------------------------------

Ashokkumar Mani  (OCP12c/11g/10g/9i, AWS SAA, M103)

Dubai , UAE | BLR , INDIA

M: +971 54 723 0075 | +91 90086 70302 | WApp : +91 81975 99922

W: https://dbatocloudsolution.blogspot.in/ | E: dbatocloud17@gmail.com