diff --git a/source/libs/index/inc/indexFstRegex.h b/source/libs/index/inc/indexFstRegex.h
index 50b9cae7ff..a58906c242 100644
--- a/source/libs/index/inc/indexFstRegex.h
+++ b/source/libs/index/inc/indexFstRegex.h
@@ -63,7 +63,7 @@ typedef struct {
 
 FstRegex *regexCreate(const char *str);
 
-void regexSetup(FstRegex *regex, uint32_t size, const char *str);
+// void regexSetup(FstRegex *regex, uint32_t size, const char *str);
 
 // uint32_t regexStart()
 
diff --git a/source/libs/index/src/indexFstRegex.c b/source/libs/index/src/indexFstRegex.c
index ec41a7f58e..2b8c8b6708 100644
--- a/source/libs/index/src/indexFstRegex.c
+++ b/source/libs/index/src/indexFstRegex.c
@@ -14,6 +14,7 @@
  */
 
 #include "indexFstRegex.h"
+#include "indexFstDfa.h"
 #include "indexFstSparse.h"
 
 FstRegex *regexCreate(const char *str) {
@@ -26,9 +27,11 @@ FstRegex *regexCreate(const char *str) {
   memcpy(orig, str, sz);
 
   regex->orig = orig;
-}
 
-void regexSetup(FstRegex *regex, uint32_t size, const char *str) {
-  // return
-  // return;
+  // construct insts based on str
+  SArray *insts = NULL;
+
+  FstDfaBuilder *builder = dfaBuilderCreate(insts);
+  regex->dfa = dfaBuilderBuild(builder);
+  return regex;
 }