/*
 * 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 "inc/tsdbMerge.h"

typedef struct {
  STsdb         *tsdb;
  TFileSetArray *fsetArr;

  int32_t  sttTrigger;
  int32_t  maxRow;
  int32_t  minRow;
  int32_t  szPage;
  int8_t   cmprAlg;
  int64_t  compactVersion;
  int64_t  cid;
  SSkmInfo skmTb[1];
  SSkmInfo skmRow[1];

  // context
  struct {
    bool       opened;
    int64_t    now;
    STFileSet *fset;
    bool       toData;
    int32_t    level;
    SSttLvl   *lvl;
    STFileObj *fobj;
    TABLEID    tbid[1];
    int32_t    bDataIdx;
    SBlockData bData[2];
  } ctx[1];

  TFileOpArray fopArr[1];

  // reader
  TSttFileReaderArray sttReaderArr[1];
  // iter
  TTsdbIterArray dataIterArr[1];
  SIterMerger   *dataIterMerger;
  TTsdbIterArray tombIterArr[1];
  SIterMerger   *tombIterMerger;
  // writer
  SSttFileWriter  *sttWriter;
  SDataFileWriter *dataWriter;
} SMerger;

static int32_t tsdbMergerOpen(SMerger *merger) {
  merger->ctx->now = taosGetTimestampMs();
  merger->maxRow = merger->tsdb->pVnode->config.tsdbCfg.maxRows;
  merger->minRow = merger->tsdb->pVnode->config.tsdbCfg.minRows;
  merger->szPage = merger->tsdb->pVnode->config.tsdbPageSize;
  merger->cmprAlg = merger->tsdb->pVnode->config.tsdbCfg.compression;
  merger->compactVersion = INT64_MAX;
  merger->cid = tsdbFSAllocEid(merger->tsdb->pFS);
  merger->ctx->opened = true;
  return 0;
}

static int32_t tsdbMergerClose(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;
  SVnode *pVnode = merger->tsdb->pVnode;

  // edit file system
  code = tsdbFSEditBegin(merger->tsdb->pFS, merger->fopArr, TSDB_FEDIT_MERGE);
  TSDB_CHECK_CODE(code, lino, _exit);

  taosThreadRwlockWrlock(&merger->tsdb->rwLock);
  code = tsdbFSEditCommit(merger->tsdb->pFS);
  if (code) {
    taosThreadRwlockUnlock(&merger->tsdb->rwLock);
    TSDB_CHECK_CODE(code, lino, _exit);
  }
  taosThreadRwlockUnlock(&merger->tsdb->rwLock);

  ASSERT(merger->dataWriter == NULL);
  ASSERT(merger->sttWriter == NULL);
  ASSERT(merger->dataIterMerger == NULL);
  ASSERT(TARRAY2_SIZE(merger->dataIterArr) == 0);
  ASSERT(TARRAY2_SIZE(merger->sttReaderArr) == 0);

  // clear the merge
  TARRAY2_DESTROY(merger->dataIterArr, NULL);
  TARRAY2_DESTROY(merger->sttReaderArr, NULL);
  TARRAY2_DESTROY(merger->fopArr, NULL);
  for (int32_t i = 0; i < ARRAY_SIZE(merger->ctx->bData); i++) {
    tBlockDataDestroy(merger->ctx->bData + i);
  }
  tDestroyTSchema(merger->skmTb->pTSchema);
  tDestroyTSchema(merger->skmRow->pTSchema);

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(pVnode), lino, code);
  }
  return code;
}

static int32_t tsdbMergeToDataTableEnd(SMerger *merger) {
  if (merger->ctx->bData[0].nRow + merger->ctx->bData[1].nRow == 0) return 0;

  int32_t code = 0;
  int32_t lino = 0;
  int32_t cidx = merger->ctx->bDataIdx;
  int32_t pidx = (cidx + 1) % 2;
  int32_t numRow = (merger->ctx->bData[pidx].nRow + merger->ctx->bData[cidx].nRow) / 2;

  if (merger->ctx->bData[pidx].nRow > 0 && numRow >= merger->minRow) {
    ASSERT(merger->ctx->bData[pidx].nRow == merger->maxRow);

    SRowInfo row[1] = {{
        .suid = merger->ctx->tbid->suid,
        .uid = merger->ctx->tbid->uid,
        .row = tsdbRowFromBlockData(merger->ctx->bData + pidx, 0),
    }};

    for (int32_t i = 0; i < numRow; i++) {
      row->row.iRow = i;

      code = tsdbDataFileWriteRow(merger->dataWriter, row);
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    code = tsdbDataFileFlush(merger->dataWriter);
    TSDB_CHECK_CODE(code, lino, _exit);

    for (int32_t i = numRow; i < merger->ctx->bData[pidx].nRow; i++) {
      row->row.iRow = i;
      code = tsdbDataFileWriteRow(merger->dataWriter, row);
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    row->row = tsdbRowFromBlockData(merger->ctx->bData + cidx, 0);
    for (int32_t i = 0; i < merger->ctx->bData[cidx].nRow; i++) {
      row->row.iRow = i;
      code = tsdbDataFileWriteRow(merger->dataWriter, row);
      TSDB_CHECK_CODE(code, lino, _exit);
    }
  } else {
    if (merger->ctx->bData[pidx].nRow > 0) {
      code = tsdbDataFileWriteBlockData(merger->dataWriter, merger->ctx->bData + cidx);
      TSDB_CHECK_CODE(code, lino, _exit);
    }
    if (merger->ctx->bData[cidx].nRow < merger->minRow) {
      code = tsdbSttFileWriteBlockData(merger->sttWriter, merger->ctx->bData + cidx);
      TSDB_CHECK_CODE(code, lino, _exit);
    } else {
      code = tsdbDataFileWriteBlockData(merger->dataWriter, merger->ctx->bData + cidx);
      TSDB_CHECK_CODE(code, lino, _exit);
    }
  }

  for (int32_t i = 0; i < ARRAY_SIZE(merger->ctx->bData); i++) {
    tBlockDataReset(merger->ctx->bData + i);
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(merger->tsdb->pVnode), lino, code);
  }
  return code;
}

static int32_t tsdbMergeToDataTableBegin(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;

  code = tsdbUpdateSkmTb(merger->tsdb, merger->ctx->tbid, merger->skmTb);
  TSDB_CHECK_CODE(code, lino, _exit);

  merger->ctx->bDataIdx = 0;
  for (int32_t i = 0; i < ARRAY_SIZE(merger->ctx->bData); i++) {
    code = tBlockDataInit(merger->ctx->bData + i, merger->ctx->tbid, merger->skmTb->pTSchema, NULL, 0);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(merger->tsdb->pVnode), lino, code);
  }
  return code;
}

static int32_t tsdbMergeToDataLevel(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;

  // data
  for (SRowInfo *row; (row = tsdbIterMergerGet(merger->dataIterMerger)) != NULL;) {
    if (row->uid != merger->ctx->tbid->uid) {
      code = tsdbMergeToDataTableEnd(merger);
      TSDB_CHECK_CODE(code, lino, _exit);

      merger->ctx->tbid->suid = row->suid;
      merger->ctx->tbid->uid = row->uid;

      code = tsdbMergeToDataTableBegin(merger);
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    TSDBKEY key[1] = {TSDBROW_KEY(&row->row)};

    if (key->version <= merger->compactVersion                 //
        && merger->ctx->bData[merger->ctx->bDataIdx].nRow > 0  //
        && merger->ctx->bData[merger->ctx->bDataIdx].aTSKEY[merger->ctx->bData[merger->ctx->bDataIdx].nRow - 1] ==
               key->ts) {
      // update
      code = tBlockDataUpdateRow(merger->ctx->bData + merger->ctx->bDataIdx, &row->row, NULL);
      TSDB_CHECK_CODE(code, lino, _exit);
    } else {
      if (merger->ctx->bData[merger->ctx->bDataIdx].nRow >= merger->maxRow) {
        int32_t idx = (merger->ctx->bDataIdx + 1) % 2;

        code = tsdbDataFileWriteBlockData(merger->dataWriter, merger->ctx->bData + idx);
        TSDB_CHECK_CODE(code, lino, _exit);

        tBlockDataClear(merger->ctx->bData + idx);

        // switch to next bData
        merger->ctx->bDataIdx = idx;
      }

      code = tBlockDataAppendRow(merger->ctx->bData + merger->ctx->bDataIdx, &row->row, NULL, row->uid);
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    code = tsdbIterMergerNext(merger->dataIterMerger);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

  code = tsdbMergeToDataTableEnd(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  // tomb
  STombRecord *record;
  while ((record = tsdbIterMergerGetTombRecord(merger->tombIterMerger))) {
    if (tsdbSttFileWriterIsOpened(merger->sttWriter)) {
      code = tsdbSttFileWriteTombRecord(merger->sttWriter, record);
      TSDB_CHECK_CODE(code, lino, _exit);
    } else {
      code = tsdbDataFileWriteTombRecord(merger->dataWriter, record);
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    code = tsdbIterMergerNext(merger->tombIterMerger);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(merger->tsdb->pVnode), lino, code);
  }
  return code;
}

static int32_t tsdbMergeToUpperLevel(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;
  int32_t vid = TD_VID(merger->tsdb->pVnode);

  // data
  SRowInfo *row;
  while ((row = tsdbIterMergerGet(merger->dataIterMerger))) {
    code = tsdbSttFileWriteRow(merger->sttWriter, row);
    TSDB_CHECK_CODE(code, lino, _exit);

    code = tsdbIterMergerNext(merger->dataIterMerger);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

  // tomb
  STombRecord *record;
  while ((record = tsdbIterMergerGetTombRecord(merger->tombIterMerger))) {
    code = tsdbSttFileWriteTombRecord(merger->sttWriter, record);
    TSDB_CHECK_CODE(code, lino, _exit);

    code = tsdbIterMergerNext(merger->tombIterMerger);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

_exit:
  if (code) {
    tsdbError("vid:%d %s failed at line %d since %s", vid, __func__, lino, tstrerror(code));
  }
  return code;
}

static int32_t tsdbMergeFileSetBeginOpenReader(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;

  merger->ctx->toData = true;
  merger->ctx->level = 0;

  // TARRAY2_FOREACH(merger->ctx->fset->lvlArr, merger->ctx->lvl) {

  for (int32_t i = 0;; ++i) {
    if (i >= TARRAY2_SIZE(merger->ctx->fset->lvlArr)) {
      merger->ctx->lvl = NULL;
      break;
    }

    merger->ctx->lvl = TARRAY2_GET(merger->ctx->fset->lvlArr, i);
    if (merger->ctx->lvl->level != merger->ctx->level || TARRAY2_SIZE(merger->ctx->lvl->fobjArr) == 0) {
      merger->ctx->toData = false;
      merger->ctx->lvl = NULL;
      break;
    }

    ASSERT(merger->ctx->lvl->level == 0 || TARRAY2_SIZE(merger->ctx->lvl->fobjArr) == 1);

    merger->ctx->fobj = TARRAY2_FIRST(merger->ctx->lvl->fobjArr);
    if (merger->ctx->fobj->f->stt->nseg < merger->sttTrigger) {
      merger->ctx->toData = false;
      break;
    } else {
      merger->ctx->level++;

      // add remove operation
      STFileOp op = {
          .optype = TSDB_FOP_REMOVE,
          .fid = merger->ctx->fset->fid,
          .of = merger->ctx->fobj->f[0],
      };
      code = TARRAY2_APPEND(merger->fopArr, op);
      TSDB_CHECK_CODE(code, lino, _exit);

      // open the reader
      SSttFileReader      *reader;
      SSttFileReaderConfig config[1] = {{
          .tsdb = merger->tsdb,
          .szPage = merger->szPage,
          .file[0] = merger->ctx->fobj->f[0],
      }};
      code = tsdbSttFileReaderOpen(merger->ctx->fobj->fname, config, &reader);
      TSDB_CHECK_CODE(code, lino, _exit);

      code = TARRAY2_APPEND(merger->sttReaderArr, reader);
      TSDB_CHECK_CODE(code, lino, _exit);
    }
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(merger->tsdb->pVnode), lino, code);
  }
  return code;
}

static int32_t tsdbMergeFileSetBeginOpenIter(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;
  int32_t vid = TD_VID(merger->tsdb->pVnode);

  SSttFileReader *sttReader;
  TARRAY2_FOREACH(merger->sttReaderArr, sttReader) {
    const TSttSegReaderArray *segReaderArr;

    code = tsdbSttFileReaderGetSegReader(sttReader, &segReaderArr);
    TSDB_CHECK_CODE(code, lino, _exit);

    SSttSegReader *segReader;
    TARRAY2_FOREACH(segReaderArr, segReader) {
      STsdbIter *iter;

      STsdbIterConfig config[1] = {{
          .type = TSDB_ITER_TYPE_STT,
          .sttReader = segReader,
      }};

      // data iter
      code = tsdbIterOpen(config, &iter);
      TSDB_CHECK_CODE(code, lino, _exit);
      code = TARRAY2_APPEND(merger->dataIterArr, iter);
      TSDB_CHECK_CODE(code, lino, _exit);

      // tomb iter
      config->type = TSDB_ITER_TYPE_STT_TOMB;
      code = tsdbIterOpen(config, &iter);
      TSDB_CHECK_CODE(code, lino, _exit);
      code = TARRAY2_APPEND(merger->tombIterArr, iter);
      TSDB_CHECK_CODE(code, lino, _exit);
    }
  }

  code = tsdbIterMergerOpen(merger->dataIterArr, &merger->dataIterMerger, false);
  TSDB_CHECK_CODE(code, lino, _exit);

  code = tsdbIterMergerOpen(merger->tombIterArr, &merger->tombIterMerger, true);
  TSDB_CHECK_CODE(code, lino, _exit);

_exit:
  if (code) {
    TSDB_ERROR_LOG(vid, lino, code);
  }
  return code;
}

static int32_t tsdbMergeFileSetBeginOpenWriter(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;
  int32_t vid = TD_VID(merger->tsdb->pVnode);

  if (merger->ctx->lvl) {
    // to existing level
    SSttFileWriterConfig config[1] = {{
        .tsdb = merger->tsdb,
        .maxRow = merger->maxRow,
        .szPage = merger->szPage,
        .cmprAlg = merger->cmprAlg,
        .compactVersion = merger->compactVersion,
        .file = merger->ctx->fobj->f[0],
    }};
    code = tsdbSttFileWriterOpen(config, &merger->sttWriter);
    TSDB_CHECK_CODE(code, lino, _exit);
  } else {
    SDiskID did[1];
    int32_t level = tsdbFidLevel(merger->ctx->fset->fid, &merger->tsdb->keepCfg, merger->ctx->now);
    if (tfsAllocDisk(merger->tsdb->pVnode->pTfs, level, did) < 0) {
      code = TSDB_CODE_FS_NO_VALID_DISK;
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    // to new level
    SSttFileWriterConfig config[1] = {{
        .tsdb = merger->tsdb,
        .maxRow = merger->maxRow,
        .szPage = merger->szPage,
        .cmprAlg = merger->cmprAlg,
        .compactVersion = merger->compactVersion,
        .file =
            {
                .type = TSDB_FTYPE_STT,
                .did = did[0],
                .fid = merger->ctx->fset->fid,
                .cid = merger->cid,
                .size = 0,
                .stt = {{
                    .level = merger->ctx->level,
                    .nseg = 0,
                }},
            },
    }};
    code = tsdbSttFileWriterOpen(config, &merger->sttWriter);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

  if (merger->ctx->toData) {
    SDiskID did;
    int32_t level = tsdbFidLevel(merger->ctx->fset->fid, &merger->tsdb->keepCfg, merger->ctx->now);

    if (tfsAllocDisk(merger->tsdb->pVnode->pTfs, level, &did) < 0) {
      code = TSDB_CODE_FS_NO_VALID_DISK;
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    SDataFileWriterConfig config[1] = {{
        .tsdb = merger->tsdb,
        .cmprAlg = merger->cmprAlg,
        .maxRow = merger->maxRow,
        .szPage = merger->szPage,
        .fid = merger->ctx->fset->fid,
        .cid = merger->cid,
        .did = did,
        .compactVersion = merger->compactVersion,
    }};

    for (int32_t i = 0; i < TSDB_FTYPE_MAX; i++) {
      if (merger->ctx->fset->farr[i]) {
        config->files[i].exist = true;
        config->files[i].file = merger->ctx->fset->farr[i]->f[0];
      } else {
        config->files[i].exist = false;
      }
    }

    code = tsdbDataFileWriterOpen(config, &merger->dataWriter);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(vid, lino, code);
  }
  return code;
}

static int32_t tsdbMergeFileSetBegin(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;

  ASSERT(TARRAY2_SIZE(merger->sttReaderArr) == 0);
  ASSERT(TARRAY2_SIZE(merger->dataIterArr) == 0);
  ASSERT(merger->dataIterMerger == NULL);
  ASSERT(merger->sttWriter == NULL);
  ASSERT(merger->dataWriter == NULL);

  merger->ctx->tbid->suid = 0;
  merger->ctx->tbid->uid = 0;
  merger->ctx->bDataIdx = 0;
  for (int32_t i = 0; i < ARRAY_SIZE(merger->ctx->bData); ++i) {
    tBlockDataReset(merger->ctx->bData + i);
  }

  // open reader
  code = tsdbMergeFileSetBeginOpenReader(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  // open iterator
  code = tsdbMergeFileSetBeginOpenIter(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  // open writer
  code = tsdbMergeFileSetBeginOpenWriter(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(merger->tsdb->pVnode), lino, code);
  }
  return code;
}

static int32_t tsdbMergeFileSetEndCloseWriter(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;
  int32_t vid = TD_VID(merger->tsdb->pVnode);

  code = tsdbSttFileWriterClose(&merger->sttWriter, 0, merger->fopArr);
  TSDB_CHECK_CODE(code, lino, _exit);

  if (merger->ctx->toData) {
    code = tsdbDataFileWriterClose(&merger->dataWriter, 0, merger->fopArr);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(vid, lino, code);
  }
  return code;
}

static int32_t tsdbMergeFileSetEndCloseIter(SMerger *merger) {
  tsdbIterMergerClose(&merger->tombIterMerger);
  TARRAY2_CLEAR(merger->tombIterArr, tsdbIterClose);
  tsdbIterMergerClose(&merger->dataIterMerger);
  TARRAY2_CLEAR(merger->dataIterArr, tsdbIterClose);
  return 0;
}

static int32_t tsdbMergeFileSetEndCloseReader(SMerger *merger) {
  TARRAY2_CLEAR(merger->sttReaderArr, tsdbSttFileReaderClose);
  return 0;
}

static int32_t tsdbMergeFileSetEnd(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;
  int32_t vid = TD_VID(merger->tsdb->pVnode);

  code = tsdbMergeFileSetEndCloseWriter(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  code = tsdbMergeFileSetEndCloseIter(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  code = tsdbMergeFileSetEndCloseReader(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

_exit:
  if (code) {
    TSDB_ERROR_LOG(vid, lino, code);
  }
  return code;
}

static int32_t tsdbMergeFileSet(SMerger *merger, STFileSet *fset) {
  int32_t code = 0;
  int32_t lino = 0;

  merger->ctx->fset = fset;
  code = tsdbMergeFileSetBegin(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  // do merge
  if (merger->ctx->toData) {
    code = tsdbMergeToDataLevel(merger);
    TSDB_CHECK_CODE(code, lino, _exit);
  } else {
    code = tsdbMergeToUpperLevel(merger);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

  code = tsdbMergeFileSetEnd(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

_exit:
  if (code) {
    tsdbError("vgId:%d %s failed at line %d since %s", TD_VID(merger->tsdb->pVnode), __func__, lino, tstrerror(code));
  } else {
    tsdbDebug("vgId:%d %s done, fid:%d", TD_VID(merger->tsdb->pVnode), __func__, fset->fid);
  }
  return 0;
}

static int32_t tsdbDoMerge(SMerger *merger) {
  int32_t code = 0;
  int32_t lino = 0;

  STFileSet *fset;
  TARRAY2_FOREACH(merger->fsetArr, fset) {
    SSttLvl *lvl = TARRAY2_SIZE(fset->lvlArr) > 0 ? TARRAY2_FIRST(fset->lvlArr) : NULL;
    if (!lvl || lvl->level != 0 || TARRAY2_SIZE(lvl->fobjArr) == 0) continue;

    STFileObj *fobj = TARRAY2_FIRST(lvl->fobjArr);
    if (fobj->f->stt->nseg < merger->sttTrigger) continue;

    if (!merger->ctx->opened) {
      code = tsdbMergerOpen(merger);
      TSDB_CHECK_CODE(code, lino, _exit);
    }

    code = tsdbMergeFileSet(merger, fset);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

  if (merger->ctx->opened) {
    code = tsdbMergerClose(merger);
    TSDB_CHECK_CODE(code, lino, _exit);
  }

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(merger->tsdb->pVnode), lino, code);
  } else {
    tsdbDebug("vgId:%d %s done", TD_VID(merger->tsdb->pVnode), __func__);
  }
  return code;
}

int32_t tsdbMerge(void *arg) {
  int32_t code = 0;
  int32_t lino = 0;
  STsdb  *tsdb = (STsdb *)arg;

  SMerger merger[1] = {{
      .tsdb = tsdb,
      .sttTrigger = tsdb->pVnode->config.sttTrigger,
  }};

  code = tsdbFSCreateCopySnapshot(tsdb->pFS, &merger->fsetArr);
  TSDB_CHECK_CODE(code, lino, _exit);

  code = tsdbDoMerge(merger);
  TSDB_CHECK_CODE(code, lino, _exit);

  tsdbFSDestroyCopySnapshot(&merger->fsetArr);

_exit:
  if (code) {
    TSDB_ERROR_LOG(TD_VID(tsdb->pVnode), lino, code);
  } else if (merger->ctx->opened) {
    tsdbDebug("vgId:%d %s done", TD_VID(tsdb->pVnode), __func__);
  }
  return code;
}