Question:
We are facing performance issue on Production Postgresql Database server which is hosted in AWS RDS server. So that we installed postgresql in EC2 instance Linux server for pre-production and tried with shared buffer value 15% of RAM value we get some positive response.
So that, Definitely we can assign shared buffer value 15% to 30 % of RAM value.
But when i trying to resize shared buffer value in Production DB server which i hosted in AWS RDS. it says invalid parameter value.
By default following value is assigned for shared buffer parameter.
shared buffer = {DBInstanceClassMemory/32768}
Please help me to resize shared buffer value is min 15 % of RAM memory.
My Instance specification is : 2 CPU, 7.5 GB RAM (db.m3.large).
Answer:
If you want to set shared_buffers to 15% of RAM, put 147456 as value instead of {DBInstanceClassMemory/32768}…
shared buffers is set as number of 8kB blocks => calculating is such:
|
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postgres=> select (15*7.5*1024*1024 /100)/8; ?column? --------------------- 147456.000000000000 (1 row) |
where:
- 15 is 15%
- 7.5 is 7.5 GB of RAM
- 1024*1024 to convert GB to KB (to unify against
shared_buffersunits - 8 is 8kB
then you have to reboot your RDS instance and check value with:
show shared_buffers; in psql