PLT-7619: Cleanup flags in data retention. (#7501)

i18n/en.json

@@ -5887,6 +5887,10 @@
     "id": "store.sql_post.permanent_delete_batch.app_error",
     "translation": "We encountered an error permanently deleting the batch of posts"
   },
+  {
+    "id": "store.sql_preference.cleanup_flags_batch.app_error",
+    "translation": "We encountered an error cleaning up the batch of flags"
+  },
   {
     "id": "store.sql_preference.delete.app_error",
     "translation": "We encountered an error while deleting preferences"

store/sql_preference_store.go

@@ -372,3 +372,55 @@ func (s SqlPreferenceStore) DeleteCategoryAndName(category string, name string)
 
 	return storeChannel
 }
+
+func (s SqlPreferenceStore) CleanupFlagsBatch(limit int64) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		query :=
+			`DELETE FROM
+				Preferences
+			WHERE
+				Category = :Category
+				AND Name IN (
+					SELECT
+						*
+					FROM (
+						SELECT
+							Preferences.Name
+						FROM
+							Preferences
+						LEFT JOIN
+							Posts
+						ON
+							Preferences.Name = Posts.Id
+						WHERE
+							Preferences.Category = :Category
+							AND Posts.Id IS null
+						LIMIT
+							:Limit
+					)
+					AS t
+				)`
+
+		sqlResult, err := s.GetMaster().Exec(query, map[string]interface{}{"Category": model.PREFERENCE_CATEGORY_FLAGGED_POST, "Limit": limit})
+		if err != nil {
+			result.Err = model.NewAppError("SqlPostStore.CleanupFlagsBatch", "store.sql_preference.cleanup_flags_batch.app_error", nil, ""+err.Error(), http.StatusInternalServerError)
+		} else {
+			rowsAffected, err1 := sqlResult.RowsAffected()
+			if err1 != nil {
+				result.Err = model.NewAppError("SqlPostStore.CleanupFlagsBatch", "store.sql_preference.cleanup_flags_batch.app_error", nil, ""+err.Error(), http.StatusInternalServerError)
+				result.Data = int64(0)
+			} else {
+				result.Data = rowsAffected
+			}
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}

store/sql_preference_store_test.go

@@ -6,6 +6,8 @@ package store
 import (
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+
 	"github.com/mattermost/mattermost-server/model"
 )
 
@@ -473,3 +475,42 @@ func TestPreferenceDeleteCategoryAndName(t *testing.T) {
 		t.Fatal("should've returned no preferences")
 	}
 }
+
+func TestPreferenceCleanupFlagsBatch(t *testing.T) {
+	Setup()
+
+	category := model.PREFERENCE_CATEGORY_FLAGGED_POST
+	userId := model.NewId()
+
+	o1 := &model.Post{}
+	o1.ChannelId = model.NewId()
+	o1.UserId = userId
+	o1.Message = "zz" + model.NewId() + "AAAAAAAAAAA"
+	o1.CreateAt = 1000
+	o1 = (<-store.Post().Save(o1)).Data.(*model.Post)
+
+	preference1 := model.Preference{
+		UserId:   userId,
+		Category: category,
+		Name:     o1.Id,
+		Value:    "true",
+	}
+
+	preference2 := model.Preference{
+		UserId:   userId,
+		Category: category,
+		Name:     model.NewId(),
+		Value:    "true",
+	}
+
+	Must(store.Preference().Save(&model.Preferences{preference1, preference2}))
+
+	result := <-store.Preference().CleanupFlagsBatch(10000)
+	assert.Nil(t, result.Err)
+
+	result = <-store.Preference().Get(userId, category, preference1.Name)
+	assert.Nil(t, result.Err)
+
+	result = <-store.Preference().Get(userId, category, preference2.Name)
+	assert.NotNil(t, result.Err)
+}

store/store.go

@@ -346,6 +346,7 @@ type PreferenceStore interface {
 	DeleteCategoryAndName(category string, name string) StoreChannel
 	PermanentDeleteByUser(userId string) StoreChannel
 	IsFeatureEnabled(feature, userId string) StoreChannel
+	CleanupFlagsBatch(limit int64) StoreChannel
 }
 
 type LicenseStore interface {