CPU Utilization goes to 100% when user register on Q2A site. Critical Issue

Question

CPU Utilization goes to 100% when user register on Q2A site.

My Application server and database server running on different devices.

This issue exist only when user register on the site.

I have also changed QA_OPTIMIZE_DISTANT_DB value to true but the problem not solved.

define('QA_OPTIMIZE_DISTANT_DB', true);

Query running on the registration page is slow for distant db.

Comments

Did you install a bunch of plugins that trigger effects when a user registers (like badge, top users, coins, avatar, privileges, extra fields, spam prevention...)? Are there some conflicts among them? Are they implemented properly (for example, a random avatar plugin with image folder but you put a ZIP file in there)? Do those plugins or core hacks create an endless loop? The worst scenario is that your site got malwares. Some fake plugins or injected malicious codes may do evil tricks with database.

BTW, remote databases are generally a bad idea for applications that do lots of queries like Q2A.

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I have checked by disabling every plugin but the same issue happens again.

I am using Serverless DB.
I think the main issue is with serverless database due to remote db.

Do you have any solution for this.

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By reading your other questions, I think you are using Amazon RDS. Amazon approach to web services is just like its FBA delivery service, they want to do everything from A to Z. The term serverless can be misleading, because their web service is more like a caching layer and there might be a horde of back-stage servers. The drawback is the constraint on RAM.

I think you will have high CP usage when questions are asked too. I believe one Q2A-related thing you can do is to clean up database. Make it more light-weighted. You may want to move your blob images to local disk, which is the same as your application.

If your qa_words table is also huge in size, also think about using Google CSE, instead of the native Q2A search module.

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I found the exact cause of the issue.

You may check here
https://www.question2answer.org/qa/88216/major-bug-in-q2a-core-for-production-sites