feat(query): add _isfilled pseudocolumn to indicate data is origin

or filled.

include/libs/function/functionMgt.h

@@ -120,6 +120,7 @@ typedef enum EFunctionType {
   FUNCTION_TYPE_WEND,
   FUNCTION_TYPE_WDURATION,
   FUNCTION_TYPE_IROWTS,
+  FUNCTION_TYPE_ISFILLED,
   FUNCTION_TYPE_TAGS,
 
   // internal function

source/libs/function/src/builtins.c

@@ -466,7 +466,7 @@ static int32_t translateStddevMerge(SFunctionNode* pFunc, char* pErrBuf, int32_t
 
 static int32_t translateWduration(SFunctionNode* pFunc, char* pErrBuf, int32_t len) {
   // pseudo column do not need to check parameters
-  pFunc->node.resType = (SDataType){.bytes = sizeof(int64_t), .type = TSDB_DATA_TYPE_BIGINT};
+  pFunc->node.resType = (SDataType){.bytes = tDataTypes[TSDB_DATA_TYPE_BIGINT].bytes, .type = TSDB_DATA_TYPE_BIGINT};
   return TSDB_CODE_SUCCESS;
 }
 
@@ -480,14 +480,21 @@ static int32_t translateNowToday(SFunctionNode* pFunc, char* pErrBuf, int32_t le
     return code;
   }
 
-  pFunc->node.resType = (SDataType){.bytes = sizeof(int64_t), .type = TSDB_DATA_TYPE_TIMESTAMP};
+  pFunc->node.resType = (SDataType){.bytes = tDataTypes[TSDB_DATA_TYPE_TIMESTAMP].bytes, .type = TSDB_DATA_TYPE_TIMESTAMP};
   return TSDB_CODE_SUCCESS;
 }
 
 static int32_t translateTimePseudoColumn(SFunctionNode* pFunc, char* pErrBuf, int32_t len) {
   // pseudo column do not need to check parameters
 
-  pFunc->node.resType = (SDataType){.bytes = sizeof(int64_t), .type = TSDB_DATA_TYPE_TIMESTAMP};
+  pFunc->node.resType = (SDataType){.bytes =tDataTypes[TSDB_DATA_TYPE_TIMESTAMP].bytes, .type = TSDB_DATA_TYPE_TIMESTAMP};
+  return TSDB_CODE_SUCCESS;
+}
+
+static int32_t translateIsFilledPseudoColumn(SFunctionNode* pFunc, char* pErrBuf, int32_t len) {
+  // pseudo column do not need to check parameters
+
+  pFunc->node.resType = (SDataType){.bytes = tDataTypes[TSDB_DATA_TYPE_BOOL].bytes, .type = TSDB_DATA_TYPE_BOOL};
   return TSDB_CODE_SUCCESS;
 }
 
@@ -3254,6 +3261,16 @@ const SBuiltinFuncDefinition funcMgtBuiltins[] = {
     .sprocessFunc = NULL,
     .finalizeFunc = NULL
   },
+  {
+    .name = "_isfilled",
+    .type = FUNCTION_TYPE_ISFILLED,
+    .classification = FUNC_MGT_PSEUDO_COLUMN_FUNC | FUNC_MGT_INTERP_PC_FUNC,
+    .translateFunc = translateIsFilledPseudoColumn,
+    .getEnvFunc   = NULL,
+    .initFunc     = NULL,
+    .sprocessFunc = NULL,
+    .finalizeFunc = NULL
+  },
   {
     .name = "_tags",
     .type = FUNCTION_TYPE_TAGS,