core: Record change in size after defrag

Signed-off-by: Abhijat Malviya <[email protected]>

Author: abhijat

src/core/compact_object.cc

@@ -1623,11 +1623,19 @@ MemoryResource* CompactObj::memory_resource() {
 }
 
 bool CompactObj::JsonConsT::DefragIfNeeded(PageUsage* page_usage) {
-  if (JsonType* old = json_ptr; ShouldDefragment(page_usage)) {
+  JsonType* old = json_ptr;
+  if (const bool should_defragment = ShouldDefragment(page_usage); should_defragment) {
+    const MiMemoryResource* mr = static_cast<MiMemoryResource*>(memory_resource());
+    const ssize_t before = mr->used();
     json_ptr = AllocateMR<JsonType>(DeepCopyJSON(old, memory_resource()));
     DeleteMR<JsonType>(old);
+    const ssize_t after = mr->used();
+    if (const ssize_t delta = after - before; delta != 0) {
+      bytes_used += delta;
+    }
     return true;
   }
+
   return false;
 }
 

src/server/engine_shard.cc

@@ -268,14 +268,19 @@ std::optional<CollectedPageStats> EngineShard::DoDefrag(CollectPageStats collect
   uint64_t attempts = 0;
 
   PageUsage page_usage{collect_page_stats, threshold};
+  DbTableStats& table_stats = slice.GetDBTable(defrag_state_.dbid)->stats;
   do {
     cur = prime_table->Traverse(cur, [&](PrimeIterator it) {
       // for each value check whether we should move it because it
       // seats on underutilized page of memory, and if so, do it.
-      bool did = it->second.DefragIfNeeded(&page_usage);
+      const ssize_t original_size = it->second.MallocUsed();
+      const bool did = it->second.DefragIfNeeded(&page_usage);
       attempts++;
       if (did) {
         reallocations++;
+        if (const ssize_t delta = it->second.MallocUsed() - original_size; delta != 0) {
+          table_stats.AddTypeMemoryUsage(it->second.ObjType(), delta);
+        }
       }
     });
     traverses_count++;