Tick not firering and I don't understand why

Hi there I have the following very simple tick script :slight_smile:
# kapacitor show pg_max_connection
ID: pg_max_connection
Error:
Template:
Type: stream
Status: enabled
Executing: true
Created: 19 Jun 20 13:59 UTC
Modified: 19 Jun 20 14:03 UTC
LastEnabled: 19 Jun 20 14:03 UTC
Databases Retention Policies: [“pgstats”.“autogen”]
TICKscript:
dbrp “pgstats”.“autogen”

var data = stream
    |from()
        .measurement('pgstats_databases')
        .groupBy('cluster', 'account')

data
    |alert()
        // critique a  95%
        .crit(lambda: float("percent_connection_usage") > 25.0)
        // formatage du message
        .message('[Kapacitor Alert] {{ index .Tags "cluster" }} , {{ index .Tags "account" }}: Connexion usage is {{ index .Tags "`percent_connection_usage`" }}')
        .email()

DOT:
digraph pg_max_connection {
graph [throughput="1.00 points/s"];

stream0 [avg_exec_time_ns="0s" errors="0" working_cardinality="0" ];
stream0 -> from1 [processed="1012503"];

from1 [avg_exec_time_ns="7.681µs" errors="0" working_cardinality="0" ];
from1 -> alert2 [processed="1012503"];

alert2 [alerts_inhibited="0" alerts_triggered="0" avg_exec_time_ns="27.564µs" crits_triggered="0" errors="0" infos_triggered="0" oks_triggered="0" warns_triggered="0" working_cardinality="17" ];
}
/ #

When I look at my grafana, I have a bunch of “percent_connection_usage” that are aboce 25 and , the alert doesn’t fire.
What am I missing ? what is wrong with the way I’ve written my alert ? Is there a way to debug this ?

Thanks
Ludo