diff --git a/src/client/src/tscSQLParser.c b/src/client/src/tscSQLParser.c
index e24c063b2e5c83dc7e98c570a4c562fdae54acdc..50c8aa0376bce3c4f36af069003336421bd8b430 100644
--- a/src/client/src/tscSQLParser.c
+++ b/src/client/src/tscSQLParser.c
@@ -914,8 +914,8 @@ static int32_t checkInvalidExprForTimeWindow(SSqlCmd* pCmd, SQueryInfo* pQueryIn
 }
 
 int32_t validateIntervalNode(SSqlObj* pSql, SQueryInfo* pQueryInfo, SSqlNode* pSqlNode) {
+  const char* msg1 = "sliding cannot be used without interval";
   const char* msg2 = "interval cannot be less than 10 ms";
-  const char* msg3 = "sliding cannot be used without interval";
 
   SSqlCmd* pCmd = &pSql->cmd;
 
@@ -924,7 +924,7 @@ int32_t validateIntervalNode(SSqlObj* pSql, SQueryInfo* pQueryInfo, SSqlNode* pS
   
   if (!TPARSER_HAS_TOKEN(pSqlNode->interval.interval)) {
     if (TPARSER_HAS_TOKEN(pSqlNode->sliding)) {
-      return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg3);
+      return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg1);
     }
 
     return TSDB_CODE_SUCCESS;
@@ -945,7 +945,7 @@ int32_t validateIntervalNode(SSqlObj* pSql, SQueryInfo* pQueryInfo, SSqlNode* pS
   if (pQueryInfo->interval.intervalUnit != 'n' && pQueryInfo->interval.intervalUnit != 'y') {
 
     // interval cannot be less than 10 milliseconds
-    if (convertTimePrecision(pQueryInfo->interval.interval, tinfo.precision, TSDB_TIME_PRECISION_MILLI) < tsMinIntervalTime) {
+    if (convertTimePrecision(pQueryInfo->interval.interval, tinfo.precision, TSDB_TIME_PRECISION_MICRO) < tsMinIntervalTime) {
       return invalidOperationMsg(tscGetErrorMsgPayload(pCmd), msg2);
     }
   }
diff --git a/src/common/src/tglobal.c b/src/common/src/tglobal.c
index 51d44add4c1672b1251be50941b49e5f87b3c019..ec98915227e34223211341971f226fda64dc0504 100644
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@@ -84,8 +84,8 @@ int32_t tsMaxNumOfOrderedResults = 100000;
 // 10 ms for sliding time, the value will changed in case of time precision changed
 int32_t tsMinSlidingTime = 10;
 
-// 10 ms for interval time range, changed accordingly
-int32_t tsMinIntervalTime = 10;
+// 1 us for interval time range, changed accordingly
+int32_t tsMinIntervalTime = 1;
 
 // 20sec, the maximum value of stream computing delay, changed accordingly
 int32_t tsMaxStreamComputDelay = 20000;
diff --git a/src/os/src/detail/osTime.c b/src/os/src/detail/osTime.c
index 4d64e14d9415a256b9ef5032db3de35bcfeedb79..847d484d9e28fd11d1df3c3b2905afcf257174dd 100644
--- a/src/os/src/detail/osTime.c
+++ b/src/os/src/detail/osTime.c
@@ -348,6 +348,7 @@ int64_t convertTimePrecision(int64_t time, int32_t fromPrecision, int32_t toPrec
                                   {1.0 / 1000000, 1.0 / 1000,       1.} };
   return (int64_t)((double)time * factors[fromPrecision][toPrecision]);
 }
+
 static int32_t getDuration(int64_t val, char unit, int64_t* result, int32_t timePrecision) {
 
   switch (unit) {
diff --git a/tests/script/general/parser/fill_us.sim b/tests/script/general/parser/fill_us.sim
index 8cd2c333475a0d0140eb5c0c8ee0fa4186fccc97..762413d0a1e975c778ccd3d31e54e0f2d347cef2 100644
--- a/tests/script/general/parser/fill_us.sim
+++ b/tests/script/general/parser/fill_us.sim
@@ -959,14 +959,14 @@ endi
 if $data31 != 9.000000000 then
   return -1
 endi
-if $data41 != null then
+if $data41 != NULL then
   print ===== $data41
   return -1
 endi
 if $data51 != 16.000000000 then
   return -1
 endi
-if $data61 != null then
+if $data61 != NULL then
    print ===== $data61
   return -1
 endi
diff --git a/tests/script/general/parser/last_cache.sim b/tests/script/general/parser/last_cache.sim
index 4b3285871b8e9414877a53aa205ba2e747e9d8e1..9c414263ecc65cc11327bbcfc7a79131984393b9 100644
--- a/tests/script/general/parser/last_cache.sim
+++ b/tests/script/general/parser/last_cache.sim
@@ -1,6 +1,6 @@
 system sh/stop_dnodes.sh
 system sh/deploy.sh -n dnode1 -i 1
-system sh/cfg.sh -n dnode1 -c walLevel -v 0
+system sh/cfg.sh -n dnode1 -c walLevel -v 1
 system sh/cfg.sh -n dnode1 -c maxtablesPerVnode -v 4
 system sh/exec.sh -n dnode1 -s start
 
diff --git a/tests/script/general/parser/testSuite.sim b/tests/script/general/parser/testSuite.sim
index 5f711389662f16e660d6fdc88a2518b6d4221efc..d7f06769a8bc2afe3c2f95acc16953ddd3b188da 100644
--- a/tests/script/general/parser/testSuite.sim
+++ b/tests/script/general/parser/testSuite.sim
@@ -12,7 +12,7 @@ run general/parser/create_tb.sim
 run general/parser/dbtbnameValidate.sim
 run general/parser/fill.sim
 run general/parser/fill_stb.sim
-#run general/parser/fill_us.sim               #
+run general/parser/fill_us.sim
 run general/parser/first_last.sim
 run general/parser/import_commit1.sim
 run general/parser/import_commit2.sim