Create GetOldestEntityCreationTime method (#14515)

This method will be used by the ES index jobs in order
to get the first timestamp to be used as the starting point
when doing indexing tasks

i18n/en.json

@@ -4228,7 +4228,7 @@
   },
   {
     "id": "ent.data_retention.channel_member_history_batch.internal_error",
-    "translation": "Failed to purge records."
+    "translation": ""
   },
   {
     "id": "ent.data_retention.generic.license.error",
@@ -4408,7 +4408,7 @@
   },
   {
     "id": "ent.get_users_in_channel_during",
-    "translation": "Failed to get users in channel during specified time period."
+    "translation": ""
   },
   {
     "id": "ent.id_loaded.license_disable.app_error",
@@ -6706,6 +6706,10 @@
     "id": "store.sql_post.get_flagged_posts.app_error",
     "translation": "Unable to get the flagged posts."
   },
+  {
+    "id": "store.sql_post.get_oldest_entity_creation_time.app_error",
+    "translation": "Unable to get the oldest entitiy creation time."
+  },
   {
     "id": "store.sql_post.get_parents_posts.app_error",
     "translation": "Unable to get the parent post for the channel."

store/opentracing_layer.go

@@ -4667,6 +4667,24 @@ func (s *OpenTracingLayerPostStore) GetOldest() (*model.Post, *model.AppError) {
 	return resultVar0, resultVar1
 }
 
+func (s *OpenTracingLayerPostStore) GetOldestEntityCreationTime() (int64, *model.AppError) {
+	origCtx := s.Root.Store.Context()
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "PostStore.GetOldestEntityCreationTime")
+	s.Root.Store.SetContext(newCtx)
+	defer func() {
+		s.Root.Store.SetContext(origCtx)
+	}()
+
+	defer span.Finish()
+	resultVar0, resultVar1 := s.PostStore.GetOldestEntityCreationTime()
+	if resultVar1 != nil {
+		span.LogFields(spanlog.Error(resultVar1))
+		ext.Error.Set(span, true)
+	}
+
+	return resultVar0, resultVar1
+}
+
 func (s *OpenTracingLayerPostStore) GetParentsForExportAfter(limit int, afterId string) ([]*model.PostForExport, *model.AppError) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "PostStore.GetParentsForExportAfter")

store/sqlstore/post_store.go

@@ -1779,3 +1779,26 @@ func (s *SqlPostStore) SearchPostsInTeamForUser(paramsList []*model.SearchParams
 
 	return model.MakePostSearchResults(posts, nil), nil
 }
+
+func (s *SqlPostStore) GetOldestEntityCreationTime() (int64, *model.AppError) {
+	query := s.getQueryBuilder().Select("MIN(min_createat) min_createat").
+		Suffix(`FROM (
+					(SELECT MIN(createat) min_createat FROM Posts)
+					UNION
+					(SELECT MIN(createat) min_createat FROM Users)
+					UNION
+					(SELECT MIN(createat) min_createat FROM Channels)
+				) entities`)
+	queryString, _, err := query.ToSql()
+	if err != nil {
+		return -1, model.NewAppError("SqlPostStore.GetOldestEntityCreationTime",
+			"store.sql_post.get_oldest_entity_creation_time.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	row := s.GetReplica().Db.QueryRow(queryString)
+	var oldest int64
+	if err := row.Scan(&oldest); err != nil {
+		return -1, model.NewAppError("SqlPostStore.GetOldestEntityCreationTime",
+			"store.sql_post.get_oldest_entity_creation_time.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	return oldest, nil
+}

store/store.go

@@ -270,6 +270,7 @@ type PostStore interface {
 	GetRepliesForExport(parentId string) ([]*model.ReplyForExport, *model.AppError)
 	GetDirectPostParentsForExportAfter(limit int, afterId string) ([]*model.DirectPostForExport, *model.AppError)
 	SearchPostsInTeamForUser(paramsList []*model.SearchParams, userId, teamId string, isOrSearch, includeDeletedChannels bool, page, perPage int) (*model.PostSearchResults, *model.AppError)
+	GetOldestEntityCreationTime() (int64, *model.AppError)
 }
 
 type UserStore interface {

store/storetest/mocks/PostStore.go

@@ -286,6 +286,29 @@ func (_m *PostStore) GetOldest() (*model.Post, *model.AppError) {
 	return r0, r1
 }
 
+// GetOldestEntityCreationTime provides a mock function with given fields:
+func (_m *PostStore) GetOldestEntityCreationTime() (int64, *model.AppError) {
+	ret := _m.Called()
+
+	var r0 int64
+	if rf, ok := ret.Get(0).(func() int64); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(int64)
+	}
+
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func() *model.AppError); ok {
+		r1 = rf()
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
+}
+
 // GetParentsForExportAfter provides a mock function with given fields: limit, afterId
 func (_m *PostStore) GetParentsForExportAfter(limit int, afterId string) ([]*model.PostForExport, *model.AppError) {
 	ret := _m.Called(limit, afterId)

store/timer_layer.go

@@ -4237,6 +4237,22 @@ func (s *TimerLayerPostStore) GetOldest() (*model.Post, *model.AppError) {
 	return resultVar0, resultVar1
 }
 
+func (s *TimerLayerPostStore) GetOldestEntityCreationTime() (int64, *model.AppError) {
+	start := timemodule.Now()
+
+	resultVar0, resultVar1 := s.PostStore.GetOldestEntityCreationTime()
+
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if resultVar1 == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("PostStore.GetOldestEntityCreationTime", success, elapsed)
+	}
+	return resultVar0, resultVar1
+}
+
 func (s *TimerLayerPostStore) GetParentsForExportAfter(limit int, afterId string) ([]*model.PostForExport, *model.AppError) {
 	start := timemodule.Now()