fix(perf): speed up summary retrieval of all time interval (resolve #336)

migrations/20220317_align_num_heartbeats.go

@@ -0,0 +1,56 @@
+package migrations
+
+import (
+	"github.com/emvi/logbuch"
+	"github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/models"
+	"gorm.io/gorm"
+)
+
+func init() {
+	const name = "20220317-align_num_heartbeats"
+	f := migrationFunc{
+		name: name,
+		f: func(db *gorm.DB, cfg *config.Config) error {
+			if hasRun(name, db) {
+				return nil
+			}
+
+			logbuch.Info("this may take a while!")
+
+			// find all summaries whose num_heartbeats is zero even though they have items
+			var faultyIds []uint
+
+			if err := db.Model(&models.Summary{}).
+				Distinct("summaries.id").
+				Joins("INNER JOIN summary_items ON summaries.num_heartbeats = 0 AND summaries.id = summary_items.summary_id").
+				Scan(&faultyIds).Error; err != nil {
+				return err
+			}
+
+			// update their heartbeats counter
+			result := db.
+				Table("summaries AS s1").
+				Where("s1.id IN ?", faultyIds).
+				Update(
+					"num_heartbeats",
+					db.
+						Model(&models.Heartbeat{}).
+						Select("COUNT(*)").
+						Where("user_id = ?", gorm.Expr("s1.user_id")).
+						Where("time BETWEEN ? AND ?", gorm.Expr("s1.from_time"), gorm.Expr("s1.to_time")),
+				)
+
+			if err := result.Error; err != nil {
+				return err
+			}
+
+			logbuch.Info("corrected heartbeats counter of %d summaries", result.RowsAffected)
+
+			setHasRun(name, db)
+			return nil
+		},
+	}
+
+	registerPostMigration(f)
+}