Re: Identify root-cause for intermittent spikes - Mailing list pgsql-performance

From MichaelDBA
Subject Re: Identify root-cause for intermittent spikes
Date
Msg-id 0e34d222-d3b8-02fc-f60a-0487212e0cd4@sqlexec.com
Whole thread Raw
In response to Identify root-cause for intermittent spikes  (Sengottaiyan T <techsenko@gmail.com>)
Responses Re: Identify root-cause for intermittent spikes
List pgsql-performance
Hello,

Your problem is probably, too many active, concurrent connections.  Get it from here the db directly:
select datname, usename, application_name, substring(query, 1, 80) query  from pg_stat_activity where state in ('active','idle in transaction');

Compare the number of rows returned with the number of vCPUs.  If it's more than double the number of vCPUs in your AWS instance class, then you are cpu saturated.

Regards,

Michael Vitale

Sengottaiyan T wrote on 10/11/2022 7:06 AM:

Hi All,

I'm looking for suggestions:

Environment: AWS PostgreSQL RDS instance - Version 14.3
Operations support gets intermittent alerts from the monitoring tool through AWS cloud watch metrics on Disk Queue Depth, CPU burst-credit & CPU Utilization.
I would like to understand what is causing the spike - is the number of logon's increased, (or) number of transactions per second increased, (or) SQL execution picked wrong plan and the long running (I/O, CPU or memory intensive) SQL is increasing load on server (cause and effect scenario) etc.,

Due to the reactive nature of the issues, we rely on the metrics gathered in the AWS cloud watch monitoring (for the underlying OS stats), Performance Insights (for the DB performance) and correlate SQL queries with pg_Stat_Statements view. But the data in the view is an aggregated stats. And, I'm looking to see the deltas compared to normal runs.
How should I approach and get to the root-cause?

AppDynamics is already configured for the RDS instance. Are there any open source monitoring tools available which would help to capture and visualize the deltas?    

Thanks,
Senko



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