[-] fix quoting $databases var in pgbouncer dashboard

[slardiere]

Description

with the default use of the $databases variable in Grafana, the quoting is wrong when there is only one DB selected by the user.

AI & Automation Policy

• I am the human author and take full personal responsibility for every change in this PR.
• No AI or automated generative tool was used in any part of this PR OR I have disclosed all tool(s) below.

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[0xgouda]

Can you share before and after screenshots?

[slardiere]

Before this fix, there is just empty panels with an error:

db query error: ERROR: column "dotclear" does not exist (SQLSTATE 42703)

The query is just :

select
  floor(extract(epoch from time)/120)*120 AS "time",
  avg((c - c_lag) / extract(epoch from time - time_lag)) as tps
from (
        select 
          (data->>'total_xact_count')::int8 as c, lag((data->>'total_xact_count')::int8) over w as c_lag,
          time, lag(time) over w as time_lag
        from pgbouncer_stats
        where data->>'database' in (dotclear) and dbname = 'pgb_spokane' and time BETWEEN '2026-04-03T07:09:03.82Z' AND '2026-04-03T07:24:03.82Z'
        window w as (order by data->>'database', time)        
) x
where c >= c_lag and time > time_lag
group by 1
order by 1

You can see the value dotclear which should be quoted.

Grafana manage that with a format option : https://grafana.com/docs/grafana/latest/visualizations/dashboards/variables/variable-syntax/

which gives : ${databases:singlequote} which fix this problem.

best regards,
Sébastien

[0xgouda]

LGTM, thanks for your contribution!

Note to self (to inspect later):

I am a bit confused why the upper panels give an error because the $databases var does not get quoted properly, but the below ones work, and the var gets quoted:
both used to have data->>'database' in ($databases)