diff --git a/source/libs/index/inc/indexFstRegex.h b/source/libs/index/inc/indexFstRegex.h
index 2814b5dc16..a6954afab6 100644
--- a/source/libs/index/inc/indexFstRegex.h
+++ b/source/libs/index/inc/indexFstRegex.h
@@ -28,7 +28,7 @@
 extern "C" {
 #endif
 
-typedef enum { MATCH, JUMP, SPLIT, RANGE } InstType;
+typedef enum { INS_MATCH, INS_JUMP, INS_SPLIT, INS_RANGE } InstType;
 
 typedef struct MatchValue {
 #ifdef WINDOWS
diff --git a/source/libs/index/src/indexFstDfa.c b/source/libs/index/src/indexFstDfa.c
index 3b0014f16a..fa7dbb5f1f 100644
--- a/source/libs/index/src/indexFstDfa.c
+++ b/source/libs/index/src/indexFstDfa.c
@@ -159,14 +159,14 @@ bool dfaBuilderCacheState(FstDfaBuilder *builder, FstSparseSet *set, uint32_t *r
     if (false == sparSetGet(set, i, &ip)) continue;
 
     Inst *inst = taosArrayGet(builder->dfa->insts, ip);
-    if (inst->ty == JUMP || inst->ty == SPLIT) {
+    if (inst->ty == INS_JUMP || inst->ty == INS_SPLIT) {
       continue;
-    } else if (inst->ty == RANGE) {
+    } else if (inst->ty == INS_RANGE) {
       if (taosArrayPush(tinsts, &ip) == NULL) {
         code = terrno;
         goto _exception;
       }
-    } else if (inst->ty == MATCH) {
+    } else if (inst->ty == INS_MATCH) {
       isMatch = true;
       if (taosArrayPush(tinsts, &ip) == NULL) {
         code = terrno;
@@ -234,11 +234,11 @@ void dfaAdd(FstDfa *dfa, FstSparseSet *set, uint32_t ip) {
   }
   bool  succ = sparSetAdd(set, ip, NULL);
   Inst *inst = taosArrayGet(dfa->insts, ip);
-  if (inst->ty == MATCH || inst->ty == RANGE) {
+  if (inst->ty == INS_MATCH || inst->ty == INS_RANGE) {
     // do nothing
-  } else if (inst->ty == JUMP) {
+  } else if (inst->ty == INS_JUMP) {
     dfaAdd(dfa, set, inst->jv.step);
-  } else if (inst->ty == SPLIT) {
+  } else if (inst->ty == INS_SPLIT) {
     dfaAdd(dfa, set, inst->sv.len1);
     dfaAdd(dfa, set, inst->sv.len2);
   }
@@ -253,11 +253,11 @@ bool dfaRun(FstDfa *dfa, FstSparseSet *from, FstSparseSet *to, uint8_t byte) {
     if (false == sparSetGet(from, i, &ip)) continue;
 
     Inst *inst = taosArrayGet(dfa->insts, ip);
-    if (inst->ty == JUMP || inst->ty == SPLIT) {
+    if (inst->ty == INS_JUMP || inst->ty == INS_SPLIT) {
       continue;
-    } else if (inst->ty == MATCH) {
+    } else if (inst->ty == INS_MATCH) {
       isMatch = true;
-    } else if (inst->ty == RANGE) {
+    } else if (inst->ty == INS_RANGE) {
       if (inst->rv.start <= byte && byte <= inst->rv.end) {
         dfaAdd(dfa, to, ip + 1);
       }
diff --git a/source/libs/index/test/utilUT.cc b/source/libs/index/test/utilUT.cc
index 50828eb3d8..5b22b51172 100644
--- a/source/libs/index/test/utilUT.cc
+++ b/source/libs/index/test/utilUT.cc
@@ -17,6 +17,7 @@
 #include "tglobal.h"
 #include "tskiplist.h"
 #include "tutil.h"
+#include "indexFstDfa.h"  
 
 class UtilEnv : public ::testing::Test {
  protected:
@@ -404,6 +405,23 @@ TEST_F(UtilComm, testCompress) {
     } 
   }
 }
+TEST_F(UtilComm, testfstDfa) {
+  {
+    FstDfaBuilder *builder = dfaBuilderCreate(NULL);
+    ASSERT_TRUE(builder != NULL);
+    dfaBuilderDestroy(builder);
+ }
+  {
+    SArray *pInst = taosArrayInit(32, sizeof(uint8_t));
+    for (int32_t i = 0; i < 26; i++) {
+      uint8_t v = 'a' + i;
+      taosArrayPush(pInst, &v); 
+    }
+    FstDfaBuilder *builder = dfaBuilderCreate(pInst);
+    FstDfa *dfa = dfaBuilderBuild(builder); 
+    dfaBuilderDestroy(builder);
+ }
+}