REDIS timeout Error when connecting with REDIS server.

Lata Rajput 16

Hi,

We are using Redis Server to maintain the session state management of asp.net webform application. We are using the Redis dll to connect with Redis server we are putting the configuration in web.config file (Please find the attached web.config ) and we are able to connect to server without an issue.

But when we are running the application we are getting the Redis timeout errors(Please find the attached screenshot of timeout) .We have created the sample application to stimulate the issue, so in sample application when we are generating 500 sessions with key value size more than 1 KB (Please find the attached code) , than we are continuously getting Redis Timeout errors.

Please let us know what should we do to handle this error.

136829-webconfig.txt - web.config file
136863-codetogenerate500sessionwithmorethan1kvaluesize.txt - Code To generate 500 session with more than 1kb size value.

Regards,
Lata

Anurag Sharma 17,571 Reputation points

2021-10-04T06:47:23.81+00:00

Hi @Lata Rajput , welcome to Microsoft Q&A forum.

All cache sizes come with permissible request per seconds in Azure Redis Cache. Example for C0 size cache, this value is 7500 if value size is 1 kb. If value size increases, request per sconds goes down. As you mentioned in your case, the size is greater than 1 Kb, so I assume we are hitting the limit and then requests are timing out.

https://learn.microsoft.com/en-us/azure/azure-cache-for-redis/cache-planning-faq

Could you please provide the screenshot of CPU related metrics and also how many keys are there with their size?
Lata Rajput 16 Reputation points

2021-10-05T04:51:55.933+00:00

Hi ,

We are generating 300 sessions keys with value size 1.35KB (for all keys same 1.3KB is set ) , than we are getting timeout error.

Also Please find the details of Timeout error we are getting in different scenarios in attached screenshot.

And please find the attached screenshot for CPU related metrics.!
Anurag Sharma 17,571 Reputation points

2021-10-05T06:04:40.263+00:00

Thanks for providing more information. From the value sizes it seems that the bigger values are causing the timeouts. Which redis cache size tier are your using like C0, C1 etc?
Anurag Sharma 17,571 Reputation points

2021-10-05T06:57:55.093+00:00

Also are you using Azure Redis or Redis Server on any VM?
Lata Rajput 16 Reputation points

2021-10-05T10:20:02.687+00:00

Hi,

We are using C0 cache tier and also we are not using redis server in VM .

Regards,
Lata
Anurag Sharma 17,571 Reputation points

2021-10-06T08:08:19.573+00:00

Thanks for the confirmation. I am checking it internally and will get back at the earliest.
Lata Rajput 16 Reputation points

2021-10-11T11:32:50.64+00:00

Is there any update on this ?
Anurag Sharma 17,571 Reputation points

2021-10-12T06:59:19.197+00:00
Apologies for the delayed response. I ran the below code and could not face any timeout error(C0 cache size)

cache.StringSet(i.ToString(), "<long string>");

And below is the screenshot for CPU usage:

Are you seeing the CPU spikes more than 80% here?