From 936540ea587631d63fe2c2e77458f212156c1b2c Mon Sep 17 00:00:00 2001
From: Agniva De Sarker <agnivade@yahoo.co.in>
Date: Mon, 15 Mar 2021 19:51:49 +0530
Subject: [PATCH] MM-33789: Revert fallback to master for
 GetAllProfilesInChannel (#17119)

* MM-33789: Revert fallback to master for GetAllProfilesInChannel

This fixes a regression introduced in https://github.com/mattermost/mattermost-server/pull/16911.

It was causing problems with too many invalidations and overloading the writer instance for big installations.
Reverting this does not affect correctness at all because it was done out of abundance of caution and the
idea at that point was it was to be done for all caches.

https://mattermost.atlassian.net/browse/MM-33789

```release-note
NONE
```

* fix gofmt issues
---
 store/localcachelayer/layer.go      |  7 +++----
 store/localcachelayer/user_layer.go | 26 +++-----------------------
 2 files changed, 6 insertions(+), 27 deletions(-)

diff --git a/store/localcachelayer/layer.go b/store/localcachelayer/layer.go
index 513837778b..7bc26eac6b 100644
--- a/store/localcachelayer/layer.go
+++ b/store/localcachelayer/layer.go
@@ -289,10 +289,9 @@ func NewLocalCacheLayer(baseStore store.Store, metrics einterfaces.MetricsInterf
 		return
 	}
 	localCacheStore.user = &LocalCacheUserStore{
-		UserStore:                      baseStore.User(),
-		rootStore:                      &localCacheStore,
-		userProfileByIdsInvalidations:  make(map[string]bool),
-		profilesInChannelInvalidations: make(map[string]bool),
+		UserStore:                     baseStore.User(),
+		rootStore:                     &localCacheStore,
+		userProfileByIdsInvalidations: make(map[string]bool),
 	}
 
 	// Teams
diff --git a/store/localcachelayer/user_layer.go b/store/localcachelayer/user_layer.go
index 1a19b66aa6..1fac2cf2f1 100644
--- a/store/localcachelayer/user_layer.go
+++ b/store/localcachelayer/user_layer.go
@@ -15,11 +15,9 @@ import (
 
 type LocalCacheUserStore struct {
 	store.UserStore
-	rootStore                      *LocalCacheStore
-	userProfileByIdsMut            sync.Mutex
-	userProfileByIdsInvalidations  map[string]bool
-	profilesInChannelMut           sync.Mutex
-	profilesInChannelInvalidations map[string]bool
+	rootStore                     *LocalCacheStore
+	userProfileByIdsMut           sync.Mutex
+	userProfileByIdsInvalidations map[string]bool
 }
 
 func (s *LocalCacheUserStore) handleClusterInvalidateScheme(msg *model.ClusterMessage) {
@@ -37,9 +35,6 @@ func (s *LocalCacheUserStore) handleClusterInvalidateProfilesInChannel(msg *mode
 	if msg.Data == ClearCacheMessageData {
 		s.rootStore.profilesInChannelCache.Purge()
 	} else {
-		s.profilesInChannelMut.Lock()
-		s.profilesInChannelInvalidations[msg.Data] = true
-		s.profilesInChannelMut.Unlock()
 		s.rootStore.profilesInChannelCache.Remove(msg.Data)
 	}
 }
@@ -72,9 +67,6 @@ func (s *LocalCacheUserStore) InvalidateProfilesInChannelCacheByUser(userId stri
 			var userMap map[string]*model.User
 			if err = s.rootStore.profilesInChannelCache.Get(key, &userMap); err == nil {
 				if _, userInCache := userMap[userId]; userInCache {
-					s.profilesInChannelMut.Lock()
-					s.profilesInChannelInvalidations[key] = true
-					s.profilesInChannelMut.Unlock()
 					s.rootStore.doInvalidateCacheCluster(s.rootStore.profilesInChannelCache, key)
 					if s.rootStore.metrics != nil {
 						s.rootStore.metrics.IncrementMemCacheInvalidationCounter("Profiles in Channel - Remove by User")
@@ -86,9 +78,6 @@ func (s *LocalCacheUserStore) InvalidateProfilesInChannelCacheByUser(userId stri
 }
 
 func (s *LocalCacheUserStore) InvalidateProfilesInChannelCache(channelID string) {
-	s.profilesInChannelMut.Lock()
-	s.profilesInChannelInvalidations[channelID] = true
-	s.profilesInChannelMut.Unlock()
 	s.rootStore.doInvalidateCacheCluster(s.rootStore.profilesInChannelCache, channelID)
 	if s.rootStore.metrics != nil {
 		s.rootStore.metrics.IncrementMemCacheInvalidationCounter("Profiles in Channel - Remove by Channel")
@@ -103,15 +92,6 @@ func (s *LocalCacheUserStore) GetAllProfilesInChannel(ctx context.Context, chann
 		}
 	}
 
-	// If it was invalidated, then we need to query master.
-	s.profilesInChannelMut.Lock()
-	if s.profilesInChannelInvalidations[channelId] {
-		ctx = sqlstore.WithMaster(ctx)
-		// And then remove the key from the map.
-		delete(s.profilesInChannelInvalidations, channelId)
-	}
-	s.profilesInChannelMut.Unlock()
-
 	userMap, err := s.UserStore.GetAllProfilesInChannel(ctx, channelId, allowFromCache)
 	if err != nil {
 		return nil, err