Performance improvements for 40M posts (#7708)

* Optimizing get root posts SQL query

* Setting session invalidation to be reliable

* Adding app reciever to SessionHasPermissionToUser

* Adding app reciever to SessionHasPermissionToTeam

* Adding app reciever to SessionHasPermissionTo

* Clear session cache if permission was denied

* Fixing rebase issues

* Revert "Optimizing get root posts SQL query"

This reverts commit f364757e7015cfb4ec673d0a4fc3d57cd25d8dd7.

* Fixing build

api4/preference.go

@@ -7,7 +7,6 @@ import (
 	"net/http"
 
 	l4g "github.com/alecthomas/log4go"
-	"github.com/mattermost/mattermost-server/app"
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/utils"
 )
@@ -28,7 +27,7 @@ func getPreferences(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if !app.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
+	if !c.App.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
 		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
 		return
 	}
@@ -48,7 +47,7 @@ func getPreferencesByCategory(c *Context, w http.ResponseWriter, r *http.Request
 		return
 	}
 
-	if !app.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
+	if !c.App.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
 		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
 		return
 	}
@@ -68,7 +67,7 @@ func getPreferenceByCategoryAndName(c *Context, w http.ResponseWriter, r *http.R
 		return
 	}
 
-	if !app.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
+	if !c.App.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
 		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
 		return
 	}
@@ -88,7 +87,7 @@ func updatePreferences(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if !app.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
+	if !c.App.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
 		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
 		return
 	}
@@ -113,7 +112,7 @@ func deletePreferences(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if !app.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
+	if !c.App.SessionHasPermissionToUser(c.Session, c.Params.UserId) {
 		c.SetPermissionError(model.PERMISSION_EDIT_OTHER_USERS)
 		return
 	}