Remove unneeded transaction when calling get_pstats

The Postgres implementation performs a single query, therefore it shouldn't require a transaction

Author: Kobzol

database/src/pool/sqlite.rs

@@ -859,8 +859,9 @@ impl Connection for SqliteConnection {
         series: &[u32],
         artifact_row_ids: &[Option<ArtifactIdNumber>],
     ) -> Vec<Vec<Option<f64>>> {
-        let conn = self.raw_ref();
-        let mut query = conn
+        let mut conn = self.raw_ref();
+        let tx = conn.transaction().unwrap();
+        let mut query = tx
             .prepare_cached("select min(value) from pstat where series = ? and aid = ?;")
             .unwrap();
         series

site/src/selector.rs

@@ -374,12 +374,10 @@ impl StatisticSeries {
             .map(|aid| aid.lookup(&index))
             .collect::<Vec<_>>();
 
-        let mut conn = ctxt.conn().await;
-        let mut tx = conn.transaction().await;
+        let conn = ctxt.conn().await;
 
         let start = std::time::Instant::now();
-        let res = tx
-            .conn()
+        let res = conn
             .get_pstats(&sids, &aids)
             .await
             .into_iter()