diff --git a/tests/script/sh/bit_and.c b/tests/script/sh/bit_and.c
index f3bf71ce94..2cf2157e1c 100644
--- a/tests/script/sh/bit_and.c
+++ b/tests/script/sh/bit_and.c
@@ -8,13 +8,17 @@ DLL_EXPORT int32_t bit_and_init() { return 0; }
 DLL_EXPORT int32_t bit_and_destroy() { return 0; }
 
 DLL_EXPORT int32_t bit_and(SUdfDataBlock* block, SUdfColumn* resultCol) {
+  udfTrace("block:%p, processing begins, rows:%d cols:%d", block, block->numOfRows, block->numOfCols);
+
   if (block->numOfCols < 2) {
+    udfError("block:%p, cols:%d needs to be greater than 2", block, block->numOfCols);
     return TSDB_CODE_UDF_INVALID_INPUT;
   }
 
   for (int32_t i = 0; i < block->numOfCols; ++i) {
     SUdfColumn* col = block->udfCols[i];
-    if (!(col->colMeta.type == TSDB_DATA_TYPE_INT)) {
+    if (col->colMeta.type != TSDB_DATA_TYPE_INT) {
+      udfError("block:%p, col:%d type:%d should be int(%d)", block, i, col->colMeta.type, TSDB_DATA_TYPE_INT);
       return TSDB_CODE_UDF_INVALID_INPUT;
     }
   }
@@ -23,25 +27,35 @@ DLL_EXPORT int32_t bit_and(SUdfDataBlock* block, SUdfColumn* resultCol) {
 
   for (int32_t i = 0; i < block->numOfRows; ++i) {
     if (udfColDataIsNull(block->udfCols[0], i)) {
+      udfTrace("block:%p, row:%d result is null since col:0 is null", block, i);
       udfColDataSetNull(resultCol, i);
       continue;
     }
+
     int32_t result = *(int32_t*)udfColDataGetData(block->udfCols[0], i);
-    int     j = 1;
+    udfTrace("block:%p, row:%d col:0 data:%d", block, i, result);
+
+    int32_t j = 1;
     for (; j < block->numOfCols; ++j) {
       if (udfColDataIsNull(block->udfCols[j], i)) {
+        udfTrace("block:%p, row:%d result is null since col:%d is null", block, i, j);
         udfColDataSetNull(resultCol, i);
         break;
       }
 
       char* colData = udfColDataGetData(block->udfCols[j], i);
       result &= *(int32_t*)colData;
+      udfTrace("block:%p, row:%d col:%d data:%d", block, i, j, *(int32_t*)colData);
     }
+
     if (j == block->numOfCols) {
       udfColDataSet(resultCol, i, (char*)&result, false);
+      udfTrace("block:%p, row:%d result is %d", block, i, result);
     }
   }
+
   resultData->numOfRows = block->numOfRows;
+  udfTrace("block:%p, processing completed, rows:%d, cols:%d,", block, block->numOfRows, block->numOfCols);
 
   return TSDB_CODE_SUCCESS;
 }