Error running query: unknown error occurred. Please try again later when running query from 2 different sessions

Issue Summary

A summary of the issue and the browser/OS environment in which it occurs.

Technical details:

  • Redash Version:V8
  • Browser/OS:chrome/Safari
  • How did you install Redash: docker image deployed in AWS ECS

we have a dashboard which runs a query against rds oracle instance.
When we run the query from chrome/safari concurrently or 2 people try to run it same time we get the below error for one user.

Error running query: unknown error occurred. Please try again later.

But when i tried the same query without using the parameter for the where clause this is working for both users.

Is there any known issues related to this?

I don’t have a full answer for you, but I can give context.

When a query is queued for execution, the job includes a hash of the query. So if two users run an identical query at once, it will only execute a single time. Because the queue sees the two jobs as identical. This means that the same query result will be sent to both users.

If the queries have different hashes because the parameter is a different value, then two jobs will be queued and executed separately.

So I wonder if there are concurrency limits on your data source that don’t allow multiple queries to execute at once. It just seems to work sometimes when two users execute simultaneously (but under the covers it’s still just one query).

Thanks @k4s1m for the reply. There is no limit for the oracle datasource we have.

also when we use query as "select * from query where id = {{settlement_id}} from 2 sessions it fails on one but when its used as “select * from query where id = 10” it works on both session

How many query runner workers do you have in your Redash instance? Just one or more than one?

we have 3 workers and with autoscaling enabled over 80% cpu utilization.when we do see high usage it goes upto 20 instances but right now usage is less and only 3 instances are there with less than 50% cpu usage