[GitHub] [incubator-kvrocks] PragmaTwice commented on a diff in pull request #1444: feat: add sintercard command from redis 7.0

["PragmaTwice (via GitHub)" <gi...@apache.org>]

PragmaTwice commented on code in PR #1444:
URL: https://github.com/apache/incubator-kvrocks/pull/1444#discussion_r1199579994


##########
src/types/redis_set.cc:
##########
@@ -338,19 +338,43 @@ rocksdb::Status Set::Inter(const std::vector<Slice> &keys, std::vector<std::stri
   for (const auto &member : target_members) {
     member_counters[member] = 1;
   }
+
+  bool has_limit = limit != 0;
+  bool limited = false;
   for (size_t i = 1; i < keys.size(); i++) {
     s = Members(keys[i], &target_members);
     if (!s.ok() || target_members.empty()) return s;
     for (const auto &member : target_members) {
-      if (member_counters.find(member) == member_counters.end()) continue;
+      if (member_counters.count(member) == 0) continue;
       member_counters[member]++;
+      if (has_limit && member_counters[member] == keys.size()) {

Review Comment:
   Why do we search for the `member` element three times in `member_counters` continuously? It looks so bad to me.
   
   ```c++
   auto iter = find(member); // find it
   use1(iter); // use it
   use2(iter);
   
   // **NOT**:
   use1(find(member));
   use2(find(member));
   use3(find(member));
   ```



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