clickhouse datasource is not respecting dataproxy config row_limit

[andrejshapal]

What happened:
Hello,
There is a config in grafana:
https://grafana.com/docs/grafana/latest/setup-grafana/configure-grafana/#row_limit

row_limit - Limits the number of rows that Grafana will process from SQL (relational) data sources. Default is 1000000.

This prevents Grafana from being killed in case someone did not provide explicit LIMIT in query.

In postgres datasource it looks like this:

While in clicklhouse datasource it does not respect the parameter:

What you expected to happen:
clickhouse datasource would fail to query more than 3000 rows

How to reproduce it (as minimally and precisely as possible):

Set:

   dataproxy:
      logging: "true"
      timeout: "1200"
      row_limit: "3000"

Then make a query with LIMIT 3001 and see the result.

Environment:

• Grafana version: Grafana v11.2.2 (dbf571744d)
• Plugin version: v4.6.0
• OS Grafana is installed on: linux
• User OS & Browser: MacOs Chrome

[SpencerTorres]

Interesting.. yeah I don't think it respects this at all. The query must define a LIMIT clause in order to limit rows, not sure how we can get the driver to limit it otherwise

[SpencerTorres]

not sure how we can get the driver to limit it otherwise

Looks like we can simply apply this handy limit setting: https://clickhouse.com/docs/operations/settings/settings#limit

I'm not sure where to get this config value from on the Grafana side 👀
This should be possible though. I'll look into it