AWS RDS Mssql performance issues.

Question

I have an AWS RDS Mssql and On-premise Mssql, Both servers have 4 CPUs and 16 Memory. Both servers have the same data in the table about 700k records.
When the exec query selects 1000 records first.
AWS RDS Mssql: ~2.4 seconds
On-premise Mssql: ~ 0.5 seconds.
Why is AWS RDS Mssql too slower than On-premise Mssql?

Answer

Great. So, from you answer above I understand that you now have the same execution time as on-prem after updating the indexes.   And a SQL Server on EC2 instance that you launched also has the same performance.   Looks like you're good.

Answer

This could be due to latency from the client. What is the distance between the on-prem client and SQL versus the on-prem client and RDS MSSQL?   Also, run the query on both platforms and record the query stats to determine exactly where the latency is.   Does the query involve any indexes? Are these indexes present on both platforms? Have you checked the query plan of each platform for any differences.. Are statistics up to date? Finally, is the performance of the storage the same with regard to IOPS and throughput..  perhaps there is more caching of data on-prem versus in RDS.  I hope these ideas will help you to locate the reason for the difference in query speed.

Answer

Also, I do not think that your RDS instance matches the specs you mention.

AWS RDS Mssql performance issues.

Relevant content