CODEWITHSUNDEEP
postgresqlamazon-web-servicesamazon-rds
user4104265
user4104265

Reputation: 47

What happens when AWS RDS CPU utilisation reaches100%?

I would like to know what what happens when AWS RDS CPU utilisation is 100%?

Do the database requests fail or are the requests put on hold until the CPU utilisation drops below 100%?

I'm using RDS Postgres and thanks in advance for your help.

Upvotes: 1

Views: 3808

Answers (2)

Puru Pathak
Puru Pathak

Reputation: 71

This could lead to a lot of issues namely:

  1. There is a good chance that if the CPU remains at 100% consistently, your instance will crash. Now, if this a Multi AZ instance, an automatic failover can reduce the downtime incurred due to any unexpected reboot to around 2min. However, if this is a Single AZ instance, the downtime can be significantly longer.

  2. Your Db instance won't accept any new connections despite not hitting the value of 'max_connections'. There is a good chance that some of the existing transactions will roll back due to performance degradation.

  3. Continuous spike to 100% CPU may lead to memory pressure, ie, very high swap usage and low freeable memory and an eventual instance crash.

  4. Workload will reach the threshold and read and write IOPS won't go further.

Upvotes: 0

Yeshodhan Kulkarni
Yeshodhan Kulkarni

Reputation: 2943

Your query performance will degrade. Further queries will fail.

If your RDS is the sole database instance for your application, your entire application could come to a stand still.

You will need to figure out if the CPU is peaking due to high load or if there is one such query that is consuming all the resources.

If its under heavy load, adding another replica might help if its read heavy. If its write heavy, you may need to scale up to the next instance or probably think about sharding your datasets.

Upvotes: 1

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