Fix infinite loop in dictGetHierarchy if id chain looped

dbms/src/Dictionaries/CacheDictionary.cpp

@@ -138,6 +138,11 @@ void CacheDictionary::isInImpl(
                 out[out_idx] = 1;
             }
             /// Found intermediate parent, add this value to search at next loop iteration
+            else if (children[new_children_idx] == parents[parents_idx])
+            {
+                // Loop detected
+                out[out_idx] = 0;
+            }
             else
             {
                 children[new_children_idx] = parents[parents_idx];

dbms/src/Functions/FunctionsExternalDictionaries.h

@@ -1431,9 +1431,16 @@ private:
                     if (0 == id)
                         continue;
 
+
+                    auto & hierarchy = hierarchies[i];
+
+                    //Checking for loop
+                    if (std::find(std::begin(hierarchy), std::end(hierarchy), id) != std::end(hierarchy))
+                        continue;
+
                     all_zeroes = false;
                     /// place id at it's corresponding place
-                    hierarchies[i].push_back(id);
+                    hierarchy.push_back(id);
 
                     ++total_count;
                 }