diff --git a/source/libs/executor/src/eventwindowoperator.c b/source/libs/executor/src/eventwindowoperator.c
new file mode 100644
index 0000000000..e38070953a
--- /dev/null
+++ b/source/libs/executor/src/eventwindowoperator.c
@@ -0,0 +1,295 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "executorimpl.h"
+#include "filter.h"
+#include "function.h"
+#include "functionMgt.h"
+#include "tcommon.h"
+#include "tcompare.h"
+#include "tdatablock.h"
+#include "tfill.h"
+#include "ttime.h"
+
+typedef struct SEventWindowOperatorInfo {
+  SOptrBasicInfo     binfo;
+  SAggSupporter      aggSup;
+  SExprSupp          scalarSup;
+  SGroupResInfo      groupResInfo;
+  SWindowRowsSup     winSup;
+  SColumn            stateCol;  // start row index
+  bool               hasKey;
+  SStateKeys         stateKey;
+  int32_t            tsSlotId;  // primary timestamp column slot id
+  STimeWindowAggSupp twAggSup;
+} SEventWindowOperatorInfo;
+
+static int32_t openEventWindowAggOptr(SOperatorInfo* pOperator);
+static void destroyEWindowOperatorInfo(void* param);
+static void doEventWindowAggImpl(SOperatorInfo* pOperator, SEventWindowOperatorInfo* pInfo, SSDataBlock* pBlock);
+static SSDataBlock* doEventWindowAgg(SOperatorInfo* pOperator);
+
+SOperatorInfo* createEventwindowOperatorInfo(SOperatorInfo* downstream, SEventWinodwPhysiNode* pStateNode,
+                                             SExecTaskInfo* pTaskInfo) {
+  SEventWindowOperatorInfo* pInfo = taosMemoryCalloc(1, sizeof(SEventWindowOperatorInfo));
+  SOperatorInfo*            pOperator = taosMemoryCalloc(1, sizeof(SOperatorInfo));
+  if (pInfo == NULL || pOperator == NULL) {
+    goto _error;
+  }
+
+  int32_t      tsSlotId = ((SColumnNode*)pStateNode->window.pTspk)->slotId;
+  SColumnNode* pColNode = (SColumnNode*)((STargetNode*)pStateNode->pStartCond)->pExpr;
+
+  if (pStateNode->window.pExprs != NULL) {
+    int32_t    numOfScalarExpr = 0;
+    SExprInfo* pScalarExprInfo = createExprInfo(pStateNode->window.pExprs, NULL, &numOfScalarExpr);
+    int32_t    code = initExprSupp(&pInfo->scalarSup, pScalarExprInfo, numOfScalarExpr);
+    if (code != TSDB_CODE_SUCCESS) {
+      goto _error;
+    }
+  }
+
+  pInfo->stateCol = extractColumnFromColumnNode(pColNode);
+  pInfo->stateKey.type = pInfo->stateCol.type;
+  pInfo->stateKey.bytes = pInfo->stateCol.bytes;
+  pInfo->stateKey.pData = taosMemoryCalloc(1, pInfo->stateCol.bytes);
+  if (pInfo->stateKey.pData == NULL) {
+    goto _error;
+  }
+
+  int32_t code = filterInitFromNode((SNode*)pStateNode->window.node.pConditions, &pOperator->exprSupp.pFilterInfo, 0);
+  if (code != TSDB_CODE_SUCCESS) {
+    goto _error;
+  }
+
+  size_t keyBufSize = sizeof(int64_t) + sizeof(int64_t) + POINTER_BYTES;
+
+  int32_t    num = 0;
+  SExprInfo* pExprInfo = createExprInfo(pStateNode->window.pFuncs, NULL, &num);
+  initResultSizeInfo(&pOperator->resultInfo, 4096);
+
+  code = initAggSup(&pOperator->exprSupp, &pInfo->aggSup, pExprInfo, num, keyBufSize, pTaskInfo->id.str);
+  if (code != TSDB_CODE_SUCCESS) {
+    goto _error;
+  }
+
+  SSDataBlock* pResBlock = createDataBlockFromDescNode(pStateNode->window.node.pOutputDataBlockDesc);
+  initBasicInfo(&pInfo->binfo, pResBlock);
+  initResultRowInfo(&pInfo->binfo.resultRowInfo);
+
+  pInfo->twAggSup =
+      (STimeWindowAggSupp){.waterMark = pStateNode->window.watermark, .calTrigger = pStateNode->window.triggerType};
+
+  initExecTimeWindowInfo(&pInfo->twAggSup.timeWindowData, &pTaskInfo->window);
+
+  pInfo->tsSlotId = tsSlotId;
+
+  setOperatorInfo(pOperator, "StateWindowOperator", QUERY_NODE_PHYSICAL_PLAN_MERGE_STATE, true, OP_NOT_OPENED, pInfo,
+                  pTaskInfo);
+  pOperator->fpSet = createOperatorFpSet(openEventWindowAggOptr, doEventWindowAgg, NULL, destroyEWindowOperatorInfo,
+                                         optrDefaultBufFn, NULL);
+
+  code = appendDownstream(pOperator, &downstream, 1);
+  if (code != TSDB_CODE_SUCCESS) {
+    goto _error;
+  }
+
+  return pOperator;
+
+_error:
+  if (pInfo != NULL) {
+    destroyEWindowOperatorInfo(pInfo);
+  }
+
+  taosMemoryFreeClear(pOperator);
+  pTaskInfo->code = code;
+  return NULL;
+}
+
+void destroyEWindowOperatorInfo(void* param) {
+  SEventWindowOperatorInfo* pInfo = (SEventWindowOperatorInfo*)param;
+  if (pInfo == NULL) {
+    return;
+  }
+
+  cleanupBasicInfo(&pInfo->binfo);
+  colDataDestroy(&pInfo->twAggSup.timeWindowData);
+
+  cleanupAggSup(&pInfo->aggSup);
+  cleanupGroupResInfo(&pInfo->groupResInfo);
+  taosMemoryFreeClear(param);
+}
+
+static int32_t openEventWindowAggOptr(SOperatorInfo* pOperator) {
+  if (OPTR_IS_OPENED(pOperator)) {
+    return TSDB_CODE_SUCCESS;
+  }
+
+  SEventWindowOperatorInfo* pInfo = pOperator->info;
+  SExecTaskInfo*            pTaskInfo = pOperator->pTaskInfo;
+
+  SExprSupp* pSup = &pOperator->exprSupp;
+  int32_t    order = TSDB_ORDER_ASC;
+  int64_t    st = taosGetTimestampUs();
+
+  SOperatorInfo* downstream = pOperator->pDownstream[0];
+  while (1) {
+    SSDataBlock* pBlock = downstream->fpSet.getNextFn(downstream);
+    if (pBlock == NULL) {
+      break;
+    }
+
+    setInputDataBlock(pSup, pBlock, order, MAIN_SCAN, true);
+    blockDataUpdateTsWindow(pBlock, pInfo->tsSlotId);
+
+    // there is an scalar expression that needs to be calculated right before apply the group aggregation.
+    if (pInfo->scalarSup.pExprInfo != NULL) {
+      pTaskInfo->code = projectApplyFunctions(pInfo->scalarSup.pExprInfo, pBlock, pBlock, pInfo->scalarSup.pCtx,
+                                              pInfo->scalarSup.numOfExprs, NULL);
+      if (pTaskInfo->code != TSDB_CODE_SUCCESS) {
+        T_LONG_JMP(pTaskInfo->env, pTaskInfo->code);
+      }
+    }
+
+    doEventWindowAggImpl(pOperator, pInfo, pBlock);
+  }
+
+  pOperator->cost.openCost = (taosGetTimestampUs() - st) / 1000.0;
+  initGroupedResultInfo(&pInfo->groupResInfo, pInfo->aggSup.pResultRowHashTable, TSDB_ORDER_ASC);
+  pOperator->status = OP_RES_TO_RETURN;
+
+  return TSDB_CODE_SUCCESS;
+}
+
+void doEventWindowAggImpl(SOperatorInfo* pOperator, SEventWindowOperatorInfo* pInfo, SSDataBlock* pBlock) {
+  SExecTaskInfo* pTaskInfo = pOperator->pTaskInfo;
+  SExprSupp*     pSup = &pOperator->exprSupp;
+
+  SColumnInfoData* pStateColInfoData = taosArrayGet(pBlock->pDataBlock, pInfo->stateCol.slotId);
+  int64_t          gid = pBlock->info.id.groupId;
+
+  bool    masterScan = true;
+  int32_t numOfOutput = pOperator->exprSupp.numOfExprs;
+  int16_t bytes = pStateColInfoData->info.bytes;
+
+  SColumnInfoData* pColInfoData = taosArrayGet(pBlock->pDataBlock, pInfo->tsSlotId);
+  TSKEY*           tsList = (TSKEY*)pColInfoData->pData;
+
+  SWindowRowsSup* pRowSup = &pInfo->winSup;
+  pRowSup->numOfRows = 0;
+
+  struct SColumnDataAgg* pAgg = NULL;
+  for (int32_t j = 0; j < pBlock->info.rows; ++j) {
+    pAgg = (pBlock->pBlockAgg != NULL) ? pBlock->pBlockAgg[pInfo->stateCol.slotId] : NULL;
+    if (colDataIsNull(pStateColInfoData, pBlock->info.rows, j, pAgg)) {
+      continue;
+    }
+
+    char* val = colDataGetData(pStateColInfoData, j);
+
+    if (gid != pRowSup->groupId || !pInfo->hasKey) {
+      // todo extract method
+      if (IS_VAR_DATA_TYPE(pInfo->stateKey.type)) {
+        varDataCopy(pInfo->stateKey.pData, val);
+      } else {
+        memcpy(pInfo->stateKey.pData, val, bytes);
+      }
+
+      pInfo->hasKey = true;
+
+      doKeepNewWindowStartInfo(pRowSup, tsList, j, gid);
+      doKeepTuple(pRowSup, tsList[j], gid);
+    } else if (compareVal(val, &pInfo->stateKey)) {
+      doKeepTuple(pRowSup, tsList[j], gid);
+      if (j == 0 && pRowSup->startRowIndex != 0) {
+        pRowSup->startRowIndex = 0;
+      }
+    } else {  // a new state window started
+      SResultRow* pResult = NULL;
+
+      // keep the time window for the closed time window.
+      STimeWindow window = pRowSup->win;
+
+      pRowSup->win.ekey = pRowSup->win.skey;
+      int32_t ret = setTimeWindowOutputBuf(&pInfo->binfo.resultRowInfo, &window, masterScan, &pResult, gid, pSup->pCtx,
+                                           numOfOutput, pSup->rowEntryInfoOffset, &pInfo->aggSup, pTaskInfo);
+      if (ret != TSDB_CODE_SUCCESS) {  // null data, too many state code
+        T_LONG_JMP(pTaskInfo->env, TSDB_CODE_APP_ERROR);
+      }
+
+      updateTimeWindowInfo(&pInfo->twAggSup.timeWindowData, &window, false);
+      applyAggFunctionOnPartialTuples(pTaskInfo, pSup->pCtx, &pInfo->twAggSup.timeWindowData, pRowSup->startRowIndex,
+                                      pRowSup->numOfRows, pBlock->info.rows, numOfOutput);
+
+      // here we start a new session window
+      doKeepNewWindowStartInfo(pRowSup, tsList, j, gid);
+      doKeepTuple(pRowSup, tsList[j], gid);
+
+      // todo extract method
+      if (IS_VAR_DATA_TYPE(pInfo->stateKey.type)) {
+        varDataCopy(pInfo->stateKey.pData, val);
+      } else {
+        memcpy(pInfo->stateKey.pData, val, bytes);
+      }
+    }
+  }
+
+  SResultRow* pResult = NULL;
+  pRowSup->win.ekey = tsList[pBlock->info.rows - 1];
+  int32_t ret = setTimeWindowOutputBuf(&pInfo->binfo.resultRowInfo, &pRowSup->win, masterScan, &pResult, gid,
+                                       pSup->pCtx, numOfOutput, pSup->rowEntryInfoOffset, &pInfo->aggSup, pTaskInfo);
+  if (ret != TSDB_CODE_SUCCESS) {  // null data, too many state code
+    T_LONG_JMP(pTaskInfo->env, TSDB_CODE_APP_ERROR);
+  }
+
+  updateTimeWindowInfo(&pInfo->twAggSup.timeWindowData, &pRowSup->win, false);
+  applyAggFunctionOnPartialTuples(pTaskInfo, pSup->pCtx, &pInfo->twAggSup.timeWindowData, pRowSup->startRowIndex, pRowSup->numOfRows,
+                                  pBlock->info.rows, numOfOutput);
+}
+
+SSDataBlock* doEventWindowAgg(SOperatorInfo* pOperator) {
+  if (pOperator->status == OP_EXEC_DONE) {
+    return NULL;
+  }
+
+  SStateWindowOperatorInfo* pInfo = pOperator->info;
+  SExecTaskInfo*            pTaskInfo = pOperator->pTaskInfo;
+  SOptrBasicInfo*           pBInfo = &pInfo->binfo;
+
+  pTaskInfo->code = pOperator->fpSet._openFn(pOperator);
+  if (pTaskInfo->code != TSDB_CODE_SUCCESS) {
+    setOperatorCompleted(pOperator);
+    return NULL;
+  }
+
+  blockDataEnsureCapacity(pBInfo->pRes, pOperator->resultInfo.capacity);
+  while (1) {
+    doBuildResultDatablock(pOperator, &pInfo->binfo, &pInfo->groupResInfo, pInfo->aggSup.pResultBuf);
+    doFilter(pBInfo->pRes, pOperator->exprSupp.pFilterInfo, NULL);
+
+    bool hasRemain = hasRemainResults(&pInfo->groupResInfo);
+    if (!hasRemain) {
+      setOperatorCompleted(pOperator);
+      break;
+    }
+
+    if (pBInfo->pRes->info.rows > 0) {
+      break;
+    }
+  }
+
+  pOperator->resultInfo.totalRows += pBInfo->pRes->info.rows;
+  return (pBInfo->pRes->info.rows == 0) ? NULL : pBInfo->pRes;
+}
diff --git a/source/libs/executor/src/timewindowoperator.c b/source/libs/executor/src/timewindowoperator.c
index 8107cea4a0..6c17df9fb1 100644
--- a/source/libs/executor/src/timewindowoperator.c
+++ b/source/libs/executor/src/timewindowoperator.c
@@ -1964,6 +1964,7 @@ static SSDataBlock* doSessionWindowAgg(SOperatorInfo* pOperator) {
   return (pBInfo->pRes->info.rows == 0) ? NULL : pBInfo->pRes;
 }
 
+// todo make this as an non-blocking operator
 SOperatorInfo* createStatewindowOperatorInfo(SOperatorInfo* downstream, SStateWinodwPhysiNode* pStateNode,
                                              SExecTaskInfo* pTaskInfo) {
   SStateWindowOperatorInfo* pInfo = taosMemoryCalloc(1, sizeof(SStateWindowOperatorInfo));