Query Blocking Between Containers in ShinyProxy on AWS

ShinyProxy
1

Hi all,

I am trying to host my ShinyProxy application on an AWS EC2 instance running Amazon Linux 2023. Say, I have two different Docker images, each containing an R Shiny app that connects to the same SQL Server database. Both images have the R Shiny app copied to the root of the image.

When I run both containers in interactive mode (docker exec -it) and manually execute the same SQL script inside each, the SELECT queries run simultaneously and I can see outputs from both containers at the same time.

However, when I launch the applications via ShinyProxy and access them through the browser, if I run a query in one application, it blocks the data retrieval in the other. All queries are read-only — there are no INSERT, UPDATE, or DELETE operations involved.

Why is this happening? How can I prevent one ShinyProxy application from blocking the other?

Thanks in advance!

2

Hi

ShinyProxy only runs the docker container, and therefore does not do anything w.r.t to the database connection.
However, please be aware, that when you open (as a single user), the same app multiple times, you will be using a single container. If the R code is written such that it blocks when executing a SQL query, the code will block for all these tabs.
If this is the problem you are having, you could update the R code to not block. A simpler approach is to run multiple containers, see User Interface | ShinyProxy