can not retrieving schema from MSSQL Server

[majidebraa]

Issue Summary

I get time out error when I want to retrieve the database schema to execute a query and get this error:

{
    "job": {
        "id": "793ec547-981f-4685-850a-f3636881742f",
        "updated_at": 0,
        "status": 4,
        "error": "b'DB-Lib error message 20009, severity 9:\\nUnable to connect: Adaptive Server is unavailable or does not exist (172.25.143.154)\\nNet-Lib error during Connection timed out (110)\\n'",
        "result": null,
        "query_result_id": null
    }
}

It is worth noting that the connection to the database is also established after a long time. Also, in the firewall and database, access through IP and port is open and the Database is accessible from MSS Management Studio.

Steps to Reproduce

1. Install the Redash from wiki instruction Link
2. Add MSSQL Database and test connection then try to add and execute query
3. Get above error

Technical details:

• Redash Version: 23.12.0-dev (dev)
• Browser/OS: Windows 10 - WSL - Chrome
• How did you install Redash: Install the Redash from wiki instruction Link

[masayuki038]

Hi @majidebraa,

I checked the query runner for MSSQL and found it gets a DB connection on every call... So, Redash doesn't use an established connection even if it already exists.

• https://github.com/getredash/redash/blob/master/redash/query_runner/mssql.py#L85
• https://github.com/getredash/redash/blob/master/redash/query_runner/mssql.py#L120

Net-Lib error during Connection timed out (110)

I think that for some reason it is not possible to connect to MSSQL when acquiring schema information. I have no idea other than that.

Please let me know if anyone has encountered a similar situation... thank you.

[dvandonkelaar]

Is this still an issue?

If I recall correctly, a connection timeout can sometimes be cases by an wrongly configured MS SQL Firewall. Can you setup a telnet session from Redash to the MS SQL server? And does the error go away when the firewall is (temporary) disabled?