MM-36743: adds last_root_post_at in channels table (#18366)

* MM-36743: adds last_root_post_at in channels table

Channel recency for CRT users should not count replies,
this commit solves that issue by adding a new column to the channels
table: LastRootPostAt.
With that new info CRT users can have recent channels to work as
expected.

* Adds the 'LastRootPostAt' to the SQL scripts

* Fixes tests

* Adds LastRootPostAt migration to v6.1

* Fixes index

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

store/sqlstore/post_store.go

@@ -170,6 +170,7 @@ func (s *SqlPostStore) SaveMultiple(posts []*model.Post) ([]*model.Post, int, er
 	channelNewPosts := make(map[string]int)
 	channelNewRootPosts := make(map[string]int)
 	maxDateNewPosts := make(map[string]int64)
+	maxDateNewRootPosts := make(map[string]int64)
 	rootIds := make(map[string]int)
 	maxDateRootIds := make(map[string]int64)
 	for idx, post := range posts {
@@ -205,10 +206,14 @@ func (s *SqlPostStore) SaveMultiple(posts []*model.Post) ([]*model.Post, int, er
 				} else {
 					channelNewRootPosts[post.ChannelId] = 1
 				}
+				maxDateNewRootPosts[post.ChannelId] = post.CreateAt
 			} else {
 				if !post.IsJoinLeaveMessage() {
 					channelNewRootPosts[post.ChannelId] = currentChannelCount + 1
 				}
+				if post.CreateAt > maxDateNewRootPosts[post.ChannelId] {
+					maxDateNewRootPosts[post.ChannelId] = post.CreateAt
+				}
 			}
 			continue
 		}
@@ -256,7 +261,7 @@ func (s *SqlPostStore) SaveMultiple(posts []*model.Post) ([]*model.Post, int, er
 	for channelId, count := range channelNewPosts {
 		countRoot := channelNewRootPosts[channelId]
 
-		if _, err = s.GetMaster().Exec("UPDATE Channels SET LastPostAt = GREATEST(:LastPostAt, LastPostAt), TotalMsgCount = TotalMsgCount + :Count, TotalMsgCountRoot = TotalMsgCountRoot + :CountRoot WHERE Id = :ChannelId", map[string]interface{}{"LastPostAt": maxDateNewPosts[channelId], "ChannelId": channelId, "Count": count, "CountRoot": countRoot}); err != nil {
+		if _, err = s.GetMaster().Exec("UPDATE Channels SET LastPostAt = GREATEST(:LastPostAt, LastPostAt), LastRootPostAt = GREATEST(:LastRootPostAt, LastRootPostAt), TotalMsgCount = TotalMsgCount + :Count, TotalMsgCountRoot = TotalMsgCountRoot + :CountRoot WHERE Id = :ChannelId", map[string]interface{}{"LastPostAt": maxDateNewPosts[channelId], "LastRootPostAt": maxDateNewRootPosts[channelId], "ChannelId": channelId, "Count": count, "CountRoot": countRoot}); err != nil {
 			mlog.Warn("Error updating Channel LastPostAt.", mlog.Err(err))
 		}
 	}

store/sqlstore/upgrade.go

@@ -1126,8 +1126,8 @@ func rootCountMigration(sqlStore *SqlStore) {
 		mlog.Error("Error updating ChannelId in Threads table", mlog.Err(err))
 	}
 	sqlStore.CreateColumnIfNotExists("Channels", "TotalMsgCountRoot", "bigint", "bigint", "0")
-	sqlStore.CreateColumnIfNotExistsNoDefault("Channels", "LastRootPostAt", "bigint", "bigint")
-	defer sqlStore.RemoveColumnIfExists("Channels", "LastRootPostAt")
+	sqlStore.CreateColumnIfNotExistsNoDefault("Channels", "LastRootAt", "bigint", "bigint")
+	defer sqlStore.RemoveColumnIfExists("Channels", "LastRootAt")
 
 	sqlStore.CreateColumnIfNotExists("ChannelMembers", "MsgCountRoot", "bigint", "bigint", "0")
 	sqlStore.AlterDefaultIfColumnExists("ChannelMembers", "MsgCountRoot", model.NewString("0"), model.NewString("0"))
@@ -1143,28 +1143,28 @@ func rootCountMigration(sqlStore *SqlStore) {
 		WHERE Posts.RootId = ''
 		GROUP BY Channels.Id
 	`
-	channelsCTE := "SELECT TotalMsgCountRoot, Id, LastRootPostAt from Channels"
+	channelsCTE := "SELECT TotalMsgCountRoot, Id, LastRootAt from Channels"
 	updateChannels := `
 		WITH q AS (` + totalMsgCountRootCTE + `)
-		UPDATE Channels SET TotalMsgCountRoot = q.newcount, LastRootPostAt=q.lastpost
+		UPDATE Channels SET TotalMsgCountRoot = q.newcount, LastRootAt=q.lastpost
 		FROM q where q.channelid=Channels.Id;
 	`
 	updateChannelMembers := `
 		WITH q as (` + channelsCTE + `)
 		UPDATE ChannelMembers CM SET MsgCountRoot=TotalMsgCountRoot
-		FROM q WHERE q.id=CM.ChannelId AND LastViewedAt >= q.lastrootpostat;
+		FROM q WHERE q.id=CM.ChannelId AND LastViewedAt >= q.lastrootat;
 	`
 	if sqlStore.DriverName() == model.DatabaseDriverMysql {
 		updateChannels = `
 			UPDATE Channels
 			INNER Join (` + totalMsgCountRootCTE + `) as q
 			ON q.channelid=Channels.Id
-			SET TotalMsgCountRoot = q.newcount, LastRootPostAt=q.lastpost;
+			SET TotalMsgCountRoot = q.newcount, LastRootAt=q.lastpost;
 		`
 		updateChannelMembers = `
 			UPDATE ChannelMembers CM
 			INNER JOIN (` + channelsCTE + `) as q
-			ON q.id=CM.ChannelId and LastViewedAt >= q.lastrootpostat
+			ON q.id=CM.ChannelId and LastViewedAt >= q.lastrootat
 			SET MsgCountRoot=TotalMsgCountRoot
 			`
 	}
@@ -1357,6 +1357,43 @@ func upgradeDatabaseToVersion610(sqlStore *SqlStore) {
 	sqlStore.AlterColumnTypeIfExists("TeamMembers", "Roles", "text", "varchar(256)")
 	sqlStore.CreateCompositeIndexIfNotExists("idx_jobs_status_type", "Jobs", []string{"Status", "Type"})
 
+	forceIndex := ""
+	if sqlStore.DriverName() == model.DatabaseDriverMysql {
+		forceIndex = "FORCE INDEX(idx_posts_channel_id_update_at)"
+	}
+
+	lastRootPostAtExists := sqlStore.DoesColumnExist("Channels", "LastRootPostAt")
+	sqlStore.CreateColumnIfNotExists("Channels", "LastRootPostAt", "bigint", "bigint", "0")
+
+	lastRootPostAtCTE := `
+		SELECT Channels.Id channelid, COALESCE(MAX(Posts.CreateAt), 0) as lastrootpost
+		FROM Channels
+		LEFT JOIN Posts ` + forceIndex + ` ON Channels.Id = Posts.ChannelId
+		WHERE Posts.RootId = ''
+		GROUP BY Channels.Id
+	`
+
+	updateChannels := `
+		WITH q AS (` + lastRootPostAtCTE + `)
+		UPDATE Channels SET LastRootPostAt=q.lastrootpost
+		FROM q where q.channelid=Channels.Id;
+	`
+
+	if sqlStore.DriverName() == model.DatabaseDriverMysql {
+		updateChannels = `
+			UPDATE Channels
+			INNER Join (` + lastRootPostAtCTE + `) as q
+			ON q.channelid=Channels.Id
+			SET LastRootPostAt=lastrootpost;
+		`
+	}
+
+	if !lastRootPostAtExists {
+		if _, err := sqlStore.GetMaster().ExecNoTimeout(updateChannels); err != nil {
+			mlog.Error("Error updating Channels table", mlog.Err(err))
+		}
+	}
+
 	// saveSchemaVersion(sqlStore, Version610)
 	// }
 }