fix slow query bug when order by other fields (#838)

* Revert "Optimize slow-query list (#835)" This reverts commit 585dc7e. * fix slow query order by Signed-off-by: crazycs520 <[email protected]> * add comment Signed-off-by: crazycs520 <[email protected]>
pingcap · Jan 8, 2021 · 4f41dd6 · 4f41dd6
1 parent 2b3274c
commit 4f41dd6
Showing 1 changed file with 21 additions and 2 deletions.
diff --git a/pkg/apiserver/slowquery/queries.go b/pkg/apiserver/slowquery/queries.go
@@ -219,10 +219,29 @@ func QuerySlowLogList(db *gorm.DB, req *GetListRequest) ([]SlowQuery, error) {
 		tx = tx.Where("DB IN (?)", req.DB)
 	}
 
+	// more robust
+	if req.OrderBy == "" {
+		req.OrderBy = "timestamp"
+	}
+
+	order, err := getProjectionsByFields(req.OrderBy)
+	if err != nil {
+		return nil, err
+	}
+	// to handle the special case: timestamp
+	// if req.OrderBy is "timestamp", then the order is "(unix_timestamp(Time) + 0E0) AS timestamp"
+	if strings.Contains(order[0], " AS ") {
+		order[0] = req.OrderBy
+	}
+	if order[0] == "timestamp" {
+		// Order by column instead of expression, see related optimization in TiDB: https://github.com/pingcap/tidb/pull/20750
+		order[0] = "Time"
+	}
+
 	if req.IsDesc {
-		tx = tx.Order("Time DESC")
+		tx = tx.Order(fmt.Sprintf("%s DESC", order[0]))
 	} else {
-		tx = tx.Order("Time ASC")
+		tx = tx.Order(fmt.Sprintf("%s ASC", order[0]))
 	}
 
 	if len(req.Plans) > 0 {