A bit better patch for #8189 : Slow connection times with a lot of simultaneous connections and active trace session present.

This also reverts commit f604c56.
The patch created by @AlexPeshkoff

Author: hvlad

src/jrd/Mapping.cpp

@@ -1091,12 +1091,7 @@ class SysPrivCache : public PermanentStorage
 				return false;
 
 			MAP_DEBUG(fprintf(stderr, "granted=%d\n", granted));
-
-			// Note, roles have no special entry with empty string as a key.
-			// Thus, don't consider it as not populated if role to check is not set (empty).
-
-			const string& roleInUse = granted ? *sqlRole : trusted_role;
-			return roleInUse.hasData() ? roles.getPrivileges(roleInUse, system_privileges) : true;
+			return roles.getPrivileges((granted ? *sqlRole : trusted_role), system_privileges);
 		}
 
 		void populate(Mapping::DbHandle& iDb, const string& name, const string* sqlRole,
@@ -1128,7 +1123,7 @@ class SysPrivCache : public PermanentStorage
 			bool getPrivileges(const string& key, UserId::Privileges& system_privileges)
 			{
 				if (!key.hasData())
-					return false;
+					return true;
 
 				UserId::Privileges p;
         		if (!get(key, p))