topic Re: Queries Hanging Indefinitely in Administration & Architecture

Queries Hanging Indefinitely

Sai03 — Thu, 15 Jan 2026 00:59:58 GMT

I spun up a databricks environment on AWS via the AWS marketplace.

All the required infrastructure such as S3, VPC, Subnets are automatically created during the process

Once I get the Databricks environment up and running - I created a cluster. I attached that cluster with a notebook and tried running simple query: Show Catalogs; The query is running indefinitely and eventually timing out, If I run select 1 that is working correctly

I can explore the catalogs, explore the volumes if I attach serverless cluster to the notebook

What is wrong with the compute that I am creating?

Re: Queries Hanging Indefinitely

emma_s — Thu, 15 Jan 2026 07:47:52 GMT

Hi,

I believe this is happening as you haven't got the right ports open to connect between your classic compute and the UC Metatstore. When you try to select 1 it works as it doesn't need to talk to the metastore but when you do show catalogs it is trying to reach the metastore and time out. You can verify this by running the following code.

import subprocess workspace_url=spark.conf.get("spark.databricks.workspaceUrl") ports = [443, 3306, 8443, 8444,] for port in ports: check_cmd = f"nc -w2 -vz $(dig +short {workspace_url} | tail -n1) {port}" result = subprocess.run(check_cmd, shell=True, capture_output=True, text=True) print(f"Port {port}:", "Success" if result.returncode == 0 else "Failure")

Note in the future you will also need ports 8445-8451 open as well as the ones in the code above. If any of these fail when you run the above script then you will need to open access to these ports. More details here https://docs.databricks.com/aws/en/security/network/classic/customer-managed-vpc

Re: Queries Hanging Indefinitely

Sai03 — Thu, 15 Jan 2026 09:10:07 GMT

Hi Emma, Thanks for your reply. I ran the code provided and from the result I could see - 8443,8444 were failure. Should I need to open these ports ?

Just to be clear - I used AWS Quickstart and the VPCs are created via the default CloudFormation template

Thanks,

Sai