diff --git a/VERSION b/VERSION
index 276cbf9..f90b1af 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.0
+2.3.2
diff --git a/lib/NGT/Common.h b/lib/NGT/Common.h
index e45fc14..dd91742 100644
--- a/lib/NGT/Common.h
+++ b/lib/NGT/Common.h
@@ -59,6 +59,7 @@ namespace NGT {
 
   class quint8 {
   public:
+    quint8(){}
     quint8(uint8_t v):value(v){}
     quint8 &operator=(uint8_t v) { value = v; return *this; }
     operator uint8_t() const { return value; }
@@ -67,6 +68,7 @@ namespace NGT {
   };
   class qsint8 {
   public:
+    qsint8(){}
     qsint8(int8_t v):value(v){}
     qsint8 &operator=(int8_t v) { value = v; return *this; }
     operator int8_t() const { return value; }
diff --git a/lib/NGT/Index.cpp b/lib/NGT/Index.cpp
index a09f51d..abbed55 100644
--- a/lib/NGT/Index.cpp
+++ b/lib/NGT/Index.cpp
@@ -142,7 +142,17 @@ NGT::Index::createGraphAndTree(const string &database, NGT::Property &prop, cons
   StdOstreamRedirector redirector(redirect);
   redirector.begin();
   try {
-    loadAndCreateIndex(*idx, database, dataFile, prop.threadPoolSize, dataSize);
+    if (idx->getObjectSpace().isQintObjectType()) {
+      idx->saveIndex(database);
+      idx->close();
+      auto append = true;
+      auto refinement = false;
+      if (!dataFile.empty()) {
+	appendFromTextObjectFile(database, dataFile, dataSize, append, refinement, prop.threadPoolSize);
+      }
+    } else {
+      loadAndCreateIndex(*idx, database, dataFile, prop.threadPoolSize, dataSize);
+    }
   } catch(Exception &err) {
     delete idx;
     redirector.end();
@@ -169,7 +179,17 @@ NGT::Index::createGraph(const string &database, NGT::Property &prop, const strin
   StdOstreamRedirector redirector(redirect);
   redirector.begin();
   try {
-    loadAndCreateIndex(*idx, database, dataFile, prop.threadPoolSize, dataSize);
+    if (idx->getObjectSpace().isQintObjectType()) {
+      idx->saveIndex(database);
+      idx->close();
+      auto append = true;
+      auto refinement = false;
+      if (!dataFile.empty()) {
+	appendFromTextObjectFile(database, dataFile, dataSize, append, refinement, prop.threadPoolSize);
+      }
+    } else {
+      loadAndCreateIndex(*idx, database, dataFile, prop.threadPoolSize, dataSize);
+    }
   } catch(Exception &err) {
     delete idx;
     redirector.end();
@@ -248,10 +268,10 @@ NGT::Index::append(const string &database, const float *data, size_t dataSize, s
 }
 
 void 
-NGT::Index::appendFromRefinementObjectFile(const std::string &indexPath) {
+NGT::Index::appendFromRefinementObjectFile(const std::string &indexPath, size_t threadSize) {
   NGT::Index index(indexPath);
   index.appendFromRefinementObjectFile();
-  index.createIndex();
+  index.createIndex(threadSize);
   index.save();
   index.close();
 }
@@ -439,12 +459,12 @@ NGT::Index::insertFromRefinementObjectFile() {
 
 void 
 NGT::Index::appendFromTextObjectFile(const std::string &indexPath, const std::string &data, size_t dataSize,
-				     bool append, bool refinement) {
+				     bool append, bool refinement, size_t threadSize) {
 //#define APPEND_TEST
   
   NGT::Index index(indexPath);
   index.appendFromTextObjectFile(data, dataSize, append, refinement);
-  index.createIndex();
+  index.createIndex(threadSize);
   index.save();
   index.close();
 }
@@ -612,10 +632,10 @@ NGT::Index::appendFromTextObjectFile(const std::string &data, size_t dataSize, b
 
 void
 NGT::Index::appendFromBinaryObjectFile(const std::string &indexPath, const std::string &data,
-				       size_t dataSize, bool append, bool refinement) {
+				       size_t dataSize, bool append, bool refinement, size_t threadSize) {
   NGT::Index index(indexPath);
   index.appendFromBinaryObjectFile(data, dataSize, append, refinement);
-  index.createIndex();
+  index.createIndex(threadSize);
   index.save();
   index.close();
 }
diff --git a/lib/NGT/Index.h b/lib/NGT/Index.h
index df73076..276e3e5 100644
--- a/lib/NGT/Index.h
+++ b/lib/NGT/Index.h
@@ -552,14 +552,14 @@ namespace NGT {
 #endif
     static void append(const std::string &index, const std::string &dataFile, size_t threadSize, size_t dataSize);
     static void append(const std::string &index, const float *data, size_t dataSize, size_t threadSize);
-    static void appendFromRefinementObjectFile(const std::string &index);
+    static void appendFromRefinementObjectFile(const std::string &index, size_t threadSize = 0);
     void appendFromRefinementObjectFile();
     void insertFromRefinementObjectFile();
-    static void appendFromTextObjectFile(const std::string &index, const std::string &data,
-					 size_t dataSize, bool append = true, bool refinement = false);
+    static void appendFromTextObjectFile(const std::string &index, const std::string &data, size_t dataSize,
+					 bool append = true, bool refinement = false, size_t threadSize = 0);
     void appendFromTextObjectFile(const std::string &data, size_t dataSize, bool append = true, bool refinement = false);
-    static void appendFromBinaryObjectFile(const std::string &index, const std::string &data,
-					   size_t dataSize, bool append = true, bool refinement = false);
+    static void appendFromBinaryObjectFile(const std::string &index, const std::string &data, size_t dataSize,
+					   bool append = true, bool refinement = false, size_t threadSize = 0);
     void appendFromBinaryObjectFile(const std::string &data, size_t dataSize, bool apend = true, bool refinement = false);
     static void remove(const std::string &database, std::vector<ObjectID> &objects, bool force = false);
     static void exportIndex(const std::string &database, const std::string &file);
diff --git a/lib/NGT/NGTQ/QbgCli.cpp b/lib/NGT/NGTQ/QbgCli.cpp
index 17ad2b7..c8e74f6 100644
--- a/lib/NGT/NGTQ/QbgCli.cpp
+++ b/lib/NGT/NGTQ/QbgCli.cpp
@@ -97,7 +97,8 @@ class QbgCliBuildParameters : public QBG::BuildParameters {
     transform(clusterDataType.begin(), clusterDataType.end(), clusterDataType.begin(), ::tolower);
     if (clusterDataType == "-" || clusterDataType == "pq4") {
       creation.localClusterDataType = NGTQ::ClusterDataTypePQ4;
-    } else if (clusterDataType == "sqsu8" || clusterDataType == "sqs8" || clusterDataType == "sq8") {
+    } else if (clusterDataType == "sqsu8" || clusterDataType == "sqs8" || clusterDataType == "sq8" ||
+	       clusterDataType == "qsu8"  || clusterDataType == "qs8") {
       creation.localClusterDataType = NGTQ::ClusterDataTypeSQSU8;
     } else if (clusterDataType == "nq") {
       creation.localClusterDataType = NGTQ::ClusterDataTypeNQ;
diff --git a/lib/NGT/PrimitiveComparator.h b/lib/NGT/PrimitiveComparator.h
index 669fead..1836db7 100644
--- a/lib/NGT/PrimitiveComparator.h
+++ b/lib/NGT/PrimitiveComparator.h
@@ -111,21 +111,21 @@ namespace NGT {
 #if defined(NGT_NO_AVX)
     template <typename OBJECT_TYPE, typename COMPARE_TYPE>
     inline static double compareL2(const OBJECT_TYPE *a, const OBJECT_TYPE *b, size_t size) {
-      const OBJECT_TYPE *last = a + size;
-      const OBJECT_TYPE *lastgroup = last - 3;
+      auto *last = a + size;
+      auto *lastgroup = last - 3;
       COMPARE_TYPE diff0, diff1, diff2, diff3;
       double d = 0.0;
       while (a < lastgroup) {
-	diff0 = static_cast<COMPARE_TYPE>(a[0] - b[0]);
-	diff1 = static_cast<COMPARE_TYPE>(a[1] - b[1]);
-	diff2 = static_cast<COMPARE_TYPE>(a[2] - b[2]);
-	diff3 = static_cast<COMPARE_TYPE>(a[3] - b[3]);
+	diff0 = static_cast<COMPARE_TYPE>(a[0]) - b[0];
+	diff1 = static_cast<COMPARE_TYPE>(a[1]) - b[1];
+	diff2 = static_cast<COMPARE_TYPE>(a[2]) - b[2];
+	diff3 = static_cast<COMPARE_TYPE>(a[3]) - b[3];
 	d += diff0 * diff0 + diff1 * diff1 + diff2 * diff2 + diff3 * diff3;
 	a += 4;
 	b += 4;
       }
       while (a < last) {
-	diff0 = static_cast<COMPARE_TYPE>(*a++ - *b++);
+	diff0 = static_cast<COMPARE_TYPE>(*a++) - static_cast<COMPARE_TYPE>(*b++);
 	d += diff0 * diff0;
       }
       return sqrt(static_cast<double>(d));
@@ -148,6 +148,9 @@ namespace NGT {
       return compareL2<bfloat16, float>(a, b, size);
     }
 #endif
+    inline static double compareL2(const quint8 *a, const quint8 *b, size_t size) {
+      return compareL2<quint8, float>(a, b, size);
+    }
 #else
     inline static double compareL2(const float *a, const float *b, size_t size) {
       const float *last = a + size;
@@ -407,7 +410,7 @@ namespace NGT {
 
     inline static double compareL2(const qsint8 *a, const quint8 *b, size_t size) {
       NGTThrowException("Not supported.");
-      return 0.00;
+      return 0.0;
     }
 
     template <typename OBJECT_TYPE>
@@ -422,15 +425,15 @@ namespace NGT {
 
     template <typename OBJECT_TYPE, typename COMPARE_TYPE>
     static double compareL1(const OBJECT_TYPE *a, const OBJECT_TYPE *b, size_t size) {
-      const OBJECT_TYPE *last = a + size;
-      const OBJECT_TYPE *lastgroup = last - 3;
+      auto *last = a + size;
+      auto *lastgroup = last - 3;
       COMPARE_TYPE diff0, diff1, diff2, diff3;
       double d = 0.0;
       while (a < lastgroup) {
-	diff0 = (COMPARE_TYPE)(a[0] - b[0]);
-	diff1 = (COMPARE_TYPE)(a[1] - b[1]);
-	diff2 = (COMPARE_TYPE)(a[2] - b[2]);
-	diff3 = (COMPARE_TYPE)(a[3] - b[3]);
+	diff0 = (COMPARE_TYPE)(a[0]) - b[0];
+	diff1 = (COMPARE_TYPE)(a[1]) - b[1];
+	diff2 = (COMPARE_TYPE)(a[2]) - b[2];
+	diff3 = (COMPARE_TYPE)(a[3]) - b[3];
 	d += absolute(diff0) + absolute(diff1) + absolute(diff2) + absolute(diff3);
 	a += 4;
 	b += 4;
@@ -464,6 +467,12 @@ namespace NGT {
       return compareL1<bfloat16, float>(a, b, size);
     }
 #endif
+    inline static double compareL1(const quint8 *a, const quint8 *b, size_t size) {
+      return compareL1<quint8, float>(a, b, size);
+    }
+    inline static double compareL1(const qsint8 *a, const qsint8 *b, size_t size) {
+      return compareL1<qsint8, float>(a, b, size);
+    }
 #else
     inline static double compareL1(const float *a, const float *b, size_t size) {
       __m256 sum = _mm256_setzero_ps();
@@ -732,6 +741,14 @@ namespace NGT {
       return sum;
     }
 
+    inline static double compareDotProduct(const qsint8 *a, const quint8 *b, size_t size) {
+      double sum = 0.0;
+      for (size_t loc = 0; loc < size; loc++) {
+	sum += static_cast<int32_t>(a[loc]) * static_cast<int32_t>(b[loc]);
+      }
+      return sum;
+    }
+
     template <typename OBJECT_TYPE>
     inline static double compareCosine(const OBJECT_TYPE *a, const OBJECT_TYPE *b, size_t size) {
       double normA = 0.0;
@@ -1153,6 +1170,7 @@ namespace NGT {
     inline static double compareCosine(const qsint8 *a, const qsint8 *b, size_t size) {
       return compareCosine(reinterpret_cast<const uint8_t*>(a), reinterpret_cast<const uint8_t*>(b), size);
     }
+#endif    // #if defined(NGT_NO_AVX)
 
     inline static double compareNormalizedCosineSimilarity(const float *a, const float *b, size_t size) {
       auto v = 1.0 - compareDotProduct(a, b, size);
@@ -1182,7 +1200,6 @@ namespace NGT {
       auto v = max - compareDotProduct(a, b, size);
       return v;
     }
-#endif    // #if defined(NGT_NO_AVX)
 
     template <typename OBJECT_TYPE>
     inline static double compareAngleDistance(const OBJECT_TYPE *a, const OBJECT_TYPE *b, size_t size) {
@@ -1512,14 +1529,14 @@ namespace NGT {
     class L1Qsint8 {
     public:
       inline static double compare(const void *a, const void *b, size_t size) {
-	NGTThrowException("Not supported.");
+	return PrimitiveComparator::compareL1((const qsint8*)a, (const qsint8*)b, size);
       }
     };
 
     class CosineSimilarityQsint8 {
     public:
       inline static double compare(const void *a, const void *b, size_t size) {
-	NGTThrowException("Not supported.");
+	return PrimitiveComparator::compareCosineSimilarity((const qsint8*)a, (const qsint8*)b, size);
       }
     };
 
@@ -1564,7 +1581,7 @@ namespace NGT {
     class NormalizedCosineSimilarityQsint8 {
     public:
       inline static double compare(const void *a, const void *b, size_t size) {
-	float max = 127.0 * 127.0 * size;
+	float max = 127.0 * 255.0;
 	auto d = max - PrimitiveComparator::compareDotProduct((const qsint8*)a, (const qsint8*)b, size);
 	return d;
       }