Fix the result merging of IVF_PQ IP (#2953)

Signed-off-by: Nshengjun.li <shengjun.li@zilliz.com>

CHANGELOG.md

@@ -5,7 +5,8 @@ Please mark all change in change log and use the issue from GitHub
 # Milvus 0.10.2 (TBD)
 
 ## Bug
--   \#2890 Fix the wrong index size
+-   \#2890 Fix the index size caculation in cache
+-   \#2952 Fix the result merging of IVF_PQ IP
 
 ## Feature
 

core/src/scheduler/task/SearchTask.cpp

@@ -104,9 +104,8 @@ XSearchTask::XSearchTask(const std::shared_ptr<server::Context>& context, Segmen
     : Task(TaskType::SearchTask, std::move(label)), context_(context), file_(file) {
     if (file_) {
         // distance -- value 0 means two vectors equal, ascending reduce, L2/HAMMING/JACCARD/TONIMOTO ...
-        // similarity -- infinity value means two vectors equal, descending reduce, IP
-        if (file_->metric_type_ == static_cast<int>(MetricType::IP) &&
-            file_->engine_type_ != static_cast<int>(EngineType::FAISS_PQ)) {
+        // similarity -- value 1 means two vectors equal, descending reduce, IP
+        if (file_->metric_type_ == static_cast<int>(MetricType::IP)) {
             ascending_reduce = false;
         }