Read response time from Read only replicas are high in Cosmos DB

Question

Hi All,

We have configured one write and 3 read regions in the cosmos db account. The read write (primary region) is located in Us east 2 , while read only regions are West europe and Japan east. We are reading data from Cosmos account using Web API's which are also deployed globally in this same regions. When i hit the Us E2 api the reponse time is expected approx (150-200 ms), however when we hit the same API's deployed in Japan or West europe the response time is 4 secs on average. I was expecting it would fetch the data from read only replica deployed in west europe and east japan region

Note :- I am using Read only keys to fetch data from Cosmos in all geo's. But now i am blocked because of high response time in EMA and APA region.
We are using replicate data globally feature of the Cosmos to configure read and write regions.

Answer 1

Hi, @Anonymous Welcome to the Microsoft Q&A forum, and sorry for the delay in my response as I was on vacation.
It seems that you did not set region preference and it keeps hitting the US East 2 region from any application instance deployed anywhere in the world.

The following article explains how to set the PreferredLocations option and has examples for different SDK versions. Tutorial: Azure Cosmos DB global distribution tutorial for the SQL API | Microsoft Learn

Regards
Geetha