sqlite: simplify get_sensors query

By dropping the timestamp clause, the index can be used more
efficiently.

src/server/api/stats.rs

@@ -104,25 +104,23 @@ pub(crate) async fn get_sensor_names(
     _session: SessionExtractor,
     State(context): State<Arc<ServerContext>>,
 ) -> Result<impl IntoResponse, ApiError> {
-    if let EventRepo::Elastic(elastic) = &context.datastore {
-        let sensors = elastic.get_sensors().await.map_err(|err| {
+    let sensors = if let EventRepo::Elastic(elastic) = &context.datastore {
+        elastic.get_sensors().await.map_err(|err| {
             error!("Failed to get sensors: {:?}", err);
             ApiError::InternalServerError
-        })?;
-        let response = json!({
-            "data": sensors,
-        });
-        Ok(Json(response).into_response())
+        })?
     } else if let EventRepo::SQLite(sqlite) = &context.datastore {
-        let sensors = sqlite.get_sensors().await.map_err(|err| {
-            error!("Failed to get sensors from datastore: {:?}", err);
+        sqlite.get_sensors().await.map_err(|err| {
+            error!("Failed to get sensors: {:?}", err);
             ApiError::InternalServerError
-        })?;
-        let response = json!({
-            "data": sensors,
-        });
-        return Ok(Json(response).into_response());
+        })?
     } else {
         return Ok((StatusCode::NOT_IMPLEMENTED, "").into_response());
-    }
+    };
+
+    let response = json!({
+        "data": sensors,
+    });
+
+    Ok(Json(response).into_response())
 }

src/sqlite/eventrepo.rs

@@ -276,19 +276,14 @@ impl SqliteEventRepo {
     }
 
     pub async fn get_sensors(&self) -> anyhow::Result<Vec<String>> {
-        let start_time = DateTime::now().datetime - chrono::Duration::hours(24);
-        let start_time = start_time.timestamp_nanos_opt().unwrap();
+        // Turns out not putting a timestamp limit on this is much
+        // faster.
         let sql = r#"
             SELECT DISTINCT json_extract(events.source, '$.host')
             FROM events
-            WHERE timestamp >= ?
-              AND json_extract(events.source, '$.host') IS NOT NULL
+            WHERE json_extract(events.source, '$.host') IS NOT NULL
             "#;
-
-        let rows: Vec<String> = sqlx::query_scalar(sql)
-            .bind(start_time)
-            .fetch_all(&self.pool)
-            .await?;
+        let rows: Vec<String> = sqlx::query_scalar(sql).fetch_all(&self.pool).await?;
         Ok(rows)
     }
 }