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Performance Insights in RDS is not displaying pretty much any information with PostgreSQL

1

Hi,

About a week ago we activated Performance Insights for two of our database instances, both of them running with PostgreSQL 14.5

Both databases have a nice amount of activity, but for some reason no meaningful stats are being showed in the Performance Insights graphs. For example, there are only 8 queries in a 24h span for our development database, and actually just one of them belongs to the exact database where the queries are being performed (we have two different databases apart of the postgres one).

This was weird so I decided to investigate myself. On a different account, I created two different PostgreSQL databases:

  • One running Postgres 12.7
  • The other one running Postgres 15.2

I enabled Performance Insights in both of them at creation time. I waited a few minutes until the database were fully up and performed some different queries: CREATE, INSERT INTO, SELECT... and still none of them was being displayed on the Performance Insights graphs for either of the databases.

Is this normal? Am I missing any kind of configuration in the Postgres instance?

Thanks in advance.

Topics
DatabaseMigration & ModernizationAnalytics
Tags
PostgreSQLAmazon Relational Database ServiceDatabasePerformance Insights
Language
English
fd
asked a year ago1094 views
6 Answers
0

no meaningful stats are being showed in the Performance Insights graphs

Could you please share the performance insights graph / view as well? I am trying to understand if nothing at all is shown, or the values are too sparse etc

AWS
MODERATOR
Vijay
answered a year ago
  • fd
    a year ago

    Hi Vijay,

    Thanks for your answer. I attached a few days ago the screenshots you asked for. Do you need anything else?

    Regards.

  • Vijay MODERATOR
    a year ago

    Thanks for the follow up. I see some "Top waits" and "Top SQLs" showing up, that means indeed the queries you are interested in are low TPS and not being picked up in the sampling. Is it possible for you to increase the rate for these queries to confirm they show up after the rate goes up?

  • fd
    a year ago

    Hi Vijay,

    Thanks again for your answer. I checked Postgres docs and the stats should be gathered from the pg_stat_statements view. I checked this view and I'm seeing some queries from our own database, with a total_exec_time of 200-650ms. Those queries never showed up in the Performance Insights.

    Are those numbers not high enough for being picked up by the sampling?

  • fd
    a year ago

    Hi Vijay,

    It's been a couple of weeks and I've got no updates. Could you quickly help me here, please?

0

Could you share some graphs on CPU or other CW metrics just to see how busy the instance is? Ideally PI should capture some queries/sessions from the sampling point of view. I want to confirm this is not a bug and indeed low activity as answered by earlier comment.

AWS
MODERATOR
Vijay
answered a year ago
0

Hi there,

Further to the previous answers, the data load on your PostgreSQL DB instance may be below the database load threshold. If you enabled Performance Insights and you can't view your data, then check the Db load chart and Counter metrics in your Performance Insights dashboard. If you see data under Counter metrics, but not Db load chart, then your DB load might be below the database load threshold for PostgreSQL. To test and confirm, run a long-running transaction on your PostgreSQL DB instance, and then check the Performance Insights dashboard again. If the data populates, then your original data load is likely below the data load threshold.

I hope that helps :)

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SUPPORT ENGINEER
Brandon
answered a year ago
0

Hi all,

Thanks for your answers. Here are a couple of graphs that show the database activity over 1 week:

DBLoad

CPUUtilization

Something tells me that these values are too low to be logged in the Performance Insights?

fd
answered a year ago
0

Vijay,

Thanks for your answer. Here you have some Performance Insights graphs for reference, for the past week as well. Let me know if this is enough for you or if you need something else.

Counter metrics

Database load

Top SQL

Do mind that in the Top SQL, none of the queries shown belong to our production database. They belong to the default postgres database.

fd
answered a year ago
0

Because Performance Insights is a sampling method, queries that are completed in a short period of time may not be sampled.
In other words, I think the SQL you executed was not displayed because it was done quickly.

https://aws.amazon.com/rds/performance-insights/faqs/?nc1=h_ls

Performance Insights counts active sessions and records each session’s attributes about every second using a lightweight sampling mechanism. The sampled data is encrypted and aggregated to a variety of granularities and served through the API and in the DB Load chart in the Amazon RDS Management Console.

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EXPERT
Riku_Kobayashi
answered a year ago

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