Explore the statistics: a query log to drill down by client, name, view and more; storage on the dashboard

jarld keeps every answer for a while (stats.retention.queries, default 7 days) in the statistics database: time, client, view, name, type, result and what blocked it. Every client, name, view, record type, result and blocklist on the Statistics page leads to an explore page for it: answers over time, the top values of every other dimension (each a link that narrows further) and the latest answers. GET /stats/explore.

The dashboard shows the size of Jarl's databases (and the query log's rows) and, per disk Jarl uses, how full it is and the databases' share.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/config/config.go

@@ -395,6 +395,9 @@ type StatsRetention struct {
 	Minute Duration `yaml:"minute"`
 	Hour   Duration `yaml:"hour"`
 	Day    Duration `yaml:"day"`
+	// Queries is how long the query log keeps every answer, for exploring
+	// (docs/stats.md#exploring); 0 keeps none.
+	Queries Duration `yaml:"queries"`
 }
 
 // Duration is a time.Duration written as "15s" or "12h" in YAML. Days
@@ -461,7 +464,7 @@ func Default() *Config {
 			LogFile:           "/var/log/named/jarl-responses.log",
 			LogSize:           "20m",
 			LogVersions:       2,
-			Retention:         StatsRetention{Minute: Duration(7 * 24 * time.Hour), Hour: Duration(90 * 24 * time.Hour), Day: Duration(730 * 24 * time.Hour)},
+			Retention:         StatsRetention{Minute: Duration(7 * 24 * time.Hour), Hour: Duration(90 * 24 * time.Hour), Day: Duration(730 * 24 * time.Hour), Queries: Duration(7 * 24 * time.Hour)},
 			TopN:              100,
 		},
 		ACME: ACME{HTTPReq: HTTPReq{RequireHTTPS: true}, Account: ACMEAccount{Directory: "letsencrypt"},
@@ -604,6 +607,9 @@ func (s *Stats) check() error {
 	if r.Minute < Duration(time.Hour) || r.Hour < Duration(24*time.Hour) || r.Day < Duration(24*time.Hour) {
 		return fmt.Errorf("retention must keep minutes for at least 1h, hours and days for at least 1d")
 	}
+	if r.Queries < 0 || (r.Queries > 0 && r.Queries < Duration(time.Hour)) {
+		return fmt.Errorf("retention.queries must be at least 1h, or 0 for no query log")
+	}
 	if s.TopN < 10 || s.TopN > 10000 {
 		return fmt.Errorf("top_n must be between 10 and 10000")
 	}
@@ -754,6 +760,7 @@ stats:
     minute: 7d     # per-minute counters
     hour: 90d      # hourly counters and top lists
     day: 730d      # daily counters and top lists
+    queries: 7d    # every answer, to explore (who asked what); 0: none
   top_n: 100       # names and clients kept per hour and per day
   anonymize_clients: false   # store 10.10.0.0/24 instead of 10.10.0.37
   exclude_clients: []        # e.g. [127.0.0.1] to ignore local monitoring