improve concurrency handling for inventory job

internal/tasks/inventoryHelpers.go

@@ -44,8 +44,8 @@ func boolStringFromInterface(value interface{}) string {
 }
 
 // latestHourlySnapshotBefore finds the most recent hourly snapshot table prior to the given time, skipping empty tables.
-func latestHourlySnapshotBefore(ctx context.Context, dbConn *sqlx.DB, cutoff time.Time) (string, error) {
-	tables, err := listLatestHourlyWithRows(ctx, dbConn, "", cutoff.Unix(), 1, nil)
+func latestHourlySnapshotBefore(ctx context.Context, dbConn *sqlx.DB, cutoff time.Time, logger *slog.Logger) (string, error) {
+	tables, err := listLatestHourlyWithRows(ctx, dbConn, "", cutoff.Unix(), 1, logger)
 	if err != nil {
 		return "", err
 	}
@@ -103,7 +103,7 @@ LIMIT ?
 			continue
 		}
 		probed := false
-		hasRows := true
+		hasRows := count.Valid && count.Int64 > 0
 		start := time.Now()
 		if !count.Valid {
 			probed = true
@@ -141,12 +141,12 @@ LIMIT ?
 	return out, nil
 }
 
-// SnapshotTooSoon reports whether the gap between prev and curr is significantly shorter than expected (default: <50% interval).
+// SnapshotTooSoon reports whether the gap between prev and curr is significantly shorter than expected.
 func SnapshotTooSoon(prevUnix, currUnix int64, expectedSeconds int64) bool {
 	if prevUnix == 0 || currUnix == 0 || expectedSeconds <= 0 {
 		return false
 	}
-	return currUnix-prevUnix < expectedSeconds/2
+	return currUnix-prevUnix < expectedSeconds
 }
 
 // querySnapshotRows builds a SELECT with proper rebind for the given table/columns/where.