diff --git a/src/query/src/qFilterfunc.c b/src/query/src/qFilterfunc.c
index 758a445afe67a02df86b8689bc8efdb7137d9db2..3828365ec287ec9a18793453b4c7f324bfc3bfcd 100644
--- a/src/query/src/qFilterfunc.c
+++ b/src/query/src/qFilterfunc.c
@@ -184,16 +184,7 @@ bool likeOperator(SColumnFilterElem *pFilter, const char *minval, const char *ma
   } else if (type == TSDB_DATA_TYPE_NCHAR) {
     SPatternCompareInfo info = PATTERN_COMPARE_INFO_INITIALIZER;
     size_t size =  (size_t)(pFilter->filterInfo.len/TSDB_NCHAR_SIZE);
-    void *pz = calloc(size + 1, TSDB_NCHAR_SIZE);
-    if (pz == NULL) {
-      return false;
-    }
-
-    memcpy(pz, (void *) pFilter->filterInfo.pz, size * TSDB_NCHAR_SIZE);
-    int32_t ret = WCSPatternMatch((uint32_t *) pz, size, (uint32_t *) varDataVal(minval), varDataLen(minval)/TSDB_NCHAR_SIZE, &info);
-    free(pz);
-
-    return ret == TSDB_PATTERN_MATCH;
+    return WCSPatternMatch((uint32_t *) pFilter->filterInfo.pz, size, (uint32_t *) varDataVal(minval), varDataLen(minval)/TSDB_NCHAR_SIZE, &info) == TSDB_PATTERN_MATCH;
   } else {
     return false;
   }
diff --git a/src/util/inc/tcompare.h b/src/util/inc/tcompare.h
index d97a8b753ae21f6e5e35ab5a92673f425f5cfc1b..c960e95a06b7155f4d8b5874ce4447a0c346fca7 100644
--- a/src/util/inc/tcompare.h
+++ b/src/util/inc/tcompare.h
@@ -44,7 +44,7 @@ typedef struct SPatternCompareInfo {
 
 int patternMatch(const char *pattern, const char *str, size_t size, const SPatternCompareInfo *pInfo);
 
-int WCSPatternMatch(uint32_t *pattern, size_t paSize, uint32_t *str, size_t size, const SPatternCompareInfo *pInfo);
+int WCSPatternMatch(const uint32_t *pattern, size_t paSize, const uint32_t *str, size_t size, const SPatternCompareInfo *pInfo);
 
 int32_t doCompare(const char* a, const char* b, int32_t type, size_t size);
 
diff --git a/src/util/src/tcompare.c b/src/util/src/tcompare.c
index a41a2b685c96c78f7ef3f20011c49e6c6a285d6b..efddf285d9bc9ffeb03b3a5ea31a7f2d48433db7 100644
--- a/src/util/src/tcompare.c
+++ b/src/util/src/tcompare.c
@@ -386,7 +386,7 @@ taosWcscspn (const uint32_t *wcs, const uint32_t *reject)
   return count;
 }
 
-int WCSPatternMatch(uint32_t *patterStr, size_t paSize, uint32_t *str, size_t size, const SPatternCompareInfo *pInfo) {
+int WCSPatternMatch(const uint32_t *patterStr, size_t paSize, const uint32_t *str, size_t size, const SPatternCompareInfo *pInfo) {
   wchar_t c, c1;
   wchar_t matchOne = L'_';  // "_"
   wchar_t matchAll = L'%';  // "%"