When all servers (Domino, HEI & SQL) are either on the On-Premise or on the AWS instance, then there is good latency seen while doing SQL based activities. However, when Domino & HEI are on the AWS instance and the SQL server is on the On-Premise then poor latency is seen while doing same SQL based activities.
The network throughput between HEI and SQL server isn't an issue, however there seems to be a lot of latency. The trace file for the data received by the SQL server shows HEI is issuing individual row updates establishing a connection for each update. This will impact the network performance of a connection with poor latency.
Increasing the 'Number of Records to Transfer Concurrently' value for the Connection document in HEI had very limited effect and was not useful to improve latency.
HEI should issue multiple row updates in one connection to improve latency .