lsm_db *pLsm;
  pLsm = tdb_lsm(pDb);
  if( pLsm ){
    tdb_lsm_config_str(pDb, "mmap=1 autowork=1 automerge=4 worker_automerge=4");
  }
  return pLsm;
}









































#define ST_REPEAT  0
#define ST_WRITE   1
#define ST_PAUSE   2
#define ST_FETCH   3
#define ST_SCAN    4
#define ST_NSCAN   5
................................................................................
  int nContent = 0;

  TestDb *pDb;
  Datasource *pData;
  DatasourceDefn defn = { TEST_DATASOURCE_RANDOM, 0, 0, 0, 0 };
  char *zSystem = "";
  int bLsm = 1;


#ifdef NDEBUG
  /* If NDEBUG is defined, disable the dynamic memory related checks in
  ** lsmtest_mem.c. They slow things down.  */
  testMallocUninstall(tdb_lsm_env());
#endif

................................................................................
    pDb = testOpen(zSystem, !bReadonly, &rc);
  }
  if( rc!=0 ) return rc;
  if( bReadonly ){
    nContent = testCountDatabase(pDb);
  }






  for(i=0; i<aParam[ST_REPEAT] && rc==0; i++){
    int msWrite, msFetch, msScan;
    int iFetch;
    int nWrite = aParam[ST_WRITE];

    if( bReadonly ){
      msWrite = 0;
................................................................................
    printf("%d %d %d\n", i, msWrite, msFetch);
    fflush(stdout);
  }

  testClose(&pDb);
  testDatasourceFree(pData);





  return rc;
}

static void do_speed_write_hook2(
  void *pCtx,
  int bLog,
  i64 iOff,
  int nData,
  int nUs
){
  FILE *pOut = (FILE *)pCtx;
  if( bLog ) return;

  if( nData==0 ){
    fprintf(pOut, "s %s 0 0 %d\n", (bLog ? "l" : "d"), nUs);
  }else{
    fprintf(pOut, "w %s %d %d %d\n", (bLog ? "l" : "d"),
        (int)iOff, nData, nUs
    );
  }
}

int do_speed_tests(int nArg, char **azArg){

  struct DbSystem {
    const char *zLibrary;
    const char *zColor;
  } aSys[] = {
    { "sqlite3",      "black" },

  lsm_db *pLsm;
  pLsm = tdb_lsm(pDb);
  if( pLsm ){
    tdb_lsm_config_str(pDb, "mmap=1 autowork=1 automerge=4 worker_automerge=4");
  }
  return pLsm;
}

typedef struct WriteHookEvent WriteHookEvent;
struct WriteHookEvent {
  i64 iOff;
  int nData;
  int nUs;
};
WriteHookEvent prev = {0, 0, 0};

static void flushPrev(FILE *pOut){
  if( prev.nData ){
    fprintf(pOut, "w %s %lld %d %d\n", "d", prev.iOff, prev.nData, prev.nUs);
    prev.nData = 0;
  }
}

static void do_speed_write_hook2(
  void *pCtx,
  int bLog,
  i64 iOff,
  int nData,
  int nUs
){
  FILE *pOut = (FILE *)pCtx;
  if( bLog ) return;

  if( prev.nData && nData && iOff==prev.iOff+prev.nData ){
    prev.nData += nData;
    prev.nUs += nUs;
  }else{
    flushPrev(pOut);
    if( nData==0 ){
      fprintf(pOut, "s %s 0 0 %d\n", (bLog ? "l" : "d"), nUs);
    }else{
      prev.iOff = iOff;
      prev.nData = nData;
      prev.nUs = nUs;
    }
  }
}

#define ST_REPEAT  0
#define ST_WRITE   1
#define ST_PAUSE   2
#define ST_FETCH   3
#define ST_SCAN    4
#define ST_NSCAN   5
................................................................................
  int nContent = 0;

  TestDb *pDb;
  Datasource *pData;
  DatasourceDefn defn = { TEST_DATASOURCE_RANDOM, 0, 0, 0, 0 };
  char *zSystem = "";
  int bLsm = 1;
  FILE *pLog = 0;

#ifdef NDEBUG
  /* If NDEBUG is defined, disable the dynamic memory related checks in
  ** lsmtest_mem.c. They slow things down.  */
  testMallocUninstall(tdb_lsm_env());
#endif

................................................................................
    pDb = testOpen(zSystem, !bReadonly, &rc);
  }
  if( rc!=0 ) return rc;
  if( bReadonly ){
    nContent = testCountDatabase(pDb);
  }

#if 0
  pLog = fopen("/tmp/speed.log", "w");
  tdb_lsm_write_hook(pDb, do_speed_write_hook2, (void *)pLog);
#endif

  for(i=0; i<aParam[ST_REPEAT] && rc==0; i++){
    int msWrite, msFetch, msScan;
    int iFetch;
    int nWrite = aParam[ST_WRITE];

    if( bReadonly ){
      msWrite = 0;
................................................................................
    printf("%d %d %d\n", i, msWrite, msFetch);
    fflush(stdout);
  }

  testClose(&pDb);
  testDatasourceFree(pData);

  if( pLog ){
    flushPrev(pLog);
    fclose(pLog);
  }
  return rc;
}




















int do_speed_tests(int nArg, char **azArg){

  struct DbSystem {
    const char *zLibrary;
    const char *zColor;
  } aSys[] = {
    { "sqlite3",      "black" },

int lsmFsFileid(lsm_db *pDb, void **ppId, int *pnId);

/* Creating, populating, gobbling and deleting sorted runs. */
void lsmFsGobble(lsm_db *, Segment *, Pgno *, int);
int lsmFsSortedDelete(FileSystem *, Snapshot *, int, Segment *);
int lsmFsSortedFinish(FileSystem *, Segment *);
int lsmFsSortedAppend(FileSystem *, Snapshot *, Segment *, Page **);
int lsmFsSortedPadding(FileSystem *, Snapshot *, Segment *);

/* Functions to retrieve the lsm_env pointer from a FileSystem or Page object */
lsm_env *lsmFsEnv(FileSystem *);
lsm_env *lsmPageEnv(Page *);
FileSystem *lsmPageFS(Page *);

................................................................................

int lsmSaveCursors(lsm_db *pDb);
int lsmRestoreCursors(lsm_db *pDb);

void lsmSortedDumpStructure(lsm_db *pDb, Snapshot *, int, int, const char *);
void lsmFsDumpBlocklists(lsm_db *);



void lsmPutU32(u8 *, u32);
u32 lsmGetU32(u8 *);

/*
** Functions from "lsm_varint.c".
*/

int lsmFsFileid(lsm_db *pDb, void **ppId, int *pnId);

/* Creating, populating, gobbling and deleting sorted runs. */
void lsmFsGobble(lsm_db *, Segment *, Pgno *, int);
int lsmFsSortedDelete(FileSystem *, Snapshot *, int, Segment *);
int lsmFsSortedFinish(FileSystem *, Segment *);
int lsmFsSortedAppend(FileSystem *, Snapshot *, Segment *, int, Page **);
int lsmFsSortedPadding(FileSystem *, Snapshot *, Segment *);

/* Functions to retrieve the lsm_env pointer from a FileSystem or Page object */
lsm_env *lsmFsEnv(FileSystem *);
lsm_env *lsmPageEnv(Page *);
FileSystem *lsmPageFS(Page *);

................................................................................

int lsmSaveCursors(lsm_db *pDb);
int lsmRestoreCursors(lsm_db *pDb);

void lsmSortedDumpStructure(lsm_db *pDb, Snapshot *, int, int, const char *);
void lsmFsDumpBlocklists(lsm_db *);

void lsmSortedExpandBtreePage(Page *pPg, int nOrig);

void lsmPutU32(u8 *, u32);
u32 lsmGetU32(u8 *);

/*
** Functions from "lsm_varint.c".
*/

  return pPage->aData;
}

/*
** Return the page number of a page.
*/
Pgno lsmFsPageNumber(Page *pPage){
  assert( (pPage->flags & PAGE_DIRTY)==0 );
  return pPage ? pPage->iPg : 0;
}

/*
** Page pPg is currently part of the LRU list belonging to pFS. Remove
** it from the list. pPg->pLruNext and pPg->pLruPrev are cleared by this
** operation.
................................................................................
** to it. The page is writable until either lsmFsPagePersist() is called on 
** it or the ref-count drops to zero.
*/
int lsmFsSortedAppend(
  FileSystem *pFS, 
  Snapshot *pSnapshot,
  Segment *p, 

  Page **ppOut
){
  int rc = LSM_OK;
  Page *pPg = 0;
  *ppOut = 0;
  int iApp = 0;
  int iNext = 0;
  int iPrev = p->iLastPg;

  if( pFS->pCompress ){
    /* In compressed database mode the page is not assigned a page number
    ** or location in the database file at this point. This will be done
    ** by the lsmFsPagePersist() call.  */
    rc = fsPageBuffer(pFS, 1, &pPg);
    if( rc==LSM_OK ){
      pPg->pFS = pFS;
      pPg->pSeg = p;
      pPg->iPg = 0;
      pPg->flags |= PAGE_DIRTY;
      pPg->nData = pFS->nPagesize;
      assert( pPg->aData );


      pPg->nRef = 1;
      pFS->nOut++;
    }
  }else{
    if( iPrev==0 ){
      iApp = findAppendPoint(pFS);
................................................................................
      if( rc!=LSM_OK ) return rc;
      iApp = fsFirstPageOnBlock(pFS, iNext);
    }else{
      iApp = iPrev + 1;
    }

    /* If this is the first page allocated, or if the page allocated is the
     ** last in the block, allocate a new block here.  */
    if( iApp==0 || fsIsLast(pFS, iApp) ){
      int iNew;                     /* New block number */

      rc = lsmBlockAllocate(pFS->pDb, &iNew);
      if( rc!=LSM_OK ) return rc;
      if( iApp==0 ){
        iApp = fsFirstPageOnBlock(pFS, iNew);
................................................................................

  pPg->nCompress = pFS->nBuffer;
  return p->xCompress(p->pCtx, 
      (char *)pFS->aOBuffer, &pPg->nCompress, 
      (const char *)pPg->aData, pPg->nData
  );
}










































/*
** If the page passed as an argument is dirty, update the database file
** (or mapping of the database file) with its current contents and mark
** the page as clean.
**
** Return LSM_OK if the operation is a success, or an LSM error code
................................................................................
      pPg->pHashNext = pFS->apHash[iHash];
      pFS->apHash[iHash] = pPg;

      pPg->pSeg->nSize += (sizeof(aSz) * 2) + pPg->nCompress;

    }else{
      i64 iOff;                   /* Offset to write within database file */




































      iOff = (i64)pFS->nPagesize * (i64)(pPg->iPg-1);
      if( pFS->bUseMmap==0 ){
        u8 *aData = pPg->aData - (pPg->flags & PAGE_HASPREV);
        rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iOff, aData, pFS->nPagesize);
      }else if( pPg->flags & PAGE_FREE ){
        fsGrowMapping(pFS, iOff + pFS->nPagesize, &rc);
        if( rc==LSM_OK ){
          u8 *aTo = &((u8 *)(pFS->pMap))[iOff];

          memcpy(aTo, pPg->aData, pFS->nPagesize);
          lsmFree(pFS->pEnv, pPg->aData);
          pPg->aData = aTo;
          pPg->flags &= ~PAGE_FREE;
          fsPageAddToLru(pFS, pPg);
        }
      }
    }
    pPg->flags &= ~PAGE_DIRTY;
    pFS->nWrite++;

  return pPage->aData;
}

/*
** Return the page number of a page.
*/
Pgno lsmFsPageNumber(Page *pPage){
  /* assert( (pPage->flags & PAGE_DIRTY)==0 ); */
  return pPage ? pPage->iPg : 0;
}

/*
** Page pPg is currently part of the LRU list belonging to pFS. Remove
** it from the list. pPg->pLruNext and pPg->pLruPrev are cleared by this
** operation.
................................................................................
** to it. The page is writable until either lsmFsPagePersist() is called on 
** it or the ref-count drops to zero.
*/
int lsmFsSortedAppend(
  FileSystem *pFS, 
  Snapshot *pSnapshot,
  Segment *p, 
  int bDefer,
  Page **ppOut
){
  int rc = LSM_OK;
  Page *pPg = 0;
  *ppOut = 0;
  int iApp = 0;
  int iNext = 0;
  int iPrev = p->iLastPg;

  if( pFS->pCompress || bDefer ){
    /* In compressed database mode the page is not assigned a page number
    ** or location in the database file at this point. This will be done
    ** by the lsmFsPagePersist() call.  */
    rc = fsPageBuffer(pFS, 1, &pPg);
    if( rc==LSM_OK ){
      pPg->pFS = pFS;
      pPg->pSeg = p;
      pPg->iPg = 0;
      pPg->flags |= PAGE_DIRTY;
      pPg->nData = pFS->nPagesize;
      assert( pPg->aData );
      if( pFS->pCompress==0 ) pPg->nData -= 4;

      pPg->nRef = 1;
      pFS->nOut++;
    }
  }else{
    if( iPrev==0 ){
      iApp = findAppendPoint(pFS);
................................................................................
      if( rc!=LSM_OK ) return rc;
      iApp = fsFirstPageOnBlock(pFS, iNext);
    }else{
      iApp = iPrev + 1;
    }

    /* If this is the first page allocated, or if the page allocated is the
    ** last in the block, also allocate the next block here.  */
    if( iApp==0 || fsIsLast(pFS, iApp) ){
      int iNew;                     /* New block number */

      rc = lsmBlockAllocate(pFS->pDb, &iNew);
      if( rc!=LSM_OK ) return rc;
      if( iApp==0 ){
        iApp = fsFirstPageOnBlock(pFS, iNew);
................................................................................

  pPg->nCompress = pFS->nBuffer;
  return p->xCompress(p->pCtx, 
      (char *)pFS->aOBuffer, &pPg->nCompress, 
      (const char *)pPg->aData, pPg->nData
  );
}

static int fsAppendPage(
  FileSystem *pFS, 
  Segment *pSeg,
  Pgno *piNew,
  int *piPrev,
  int *piNext
){
  Pgno iPrev = pSeg->iLastPg;
  int rc;
  assert( iPrev!=0 );

  *piPrev = 0;
  *piNext = 0;

  if( fsIsLast(pFS, iPrev) ){
    /* Grab the first page on the next block (which has already be
    ** allocated). In this case set *piPrev to tell the caller to set
    ** the "previous block" pointer in the first 4 bytes of the page.
    */
    int iNext;
    int iBlk = fsPageToBlock(pFS, iPrev);
    rc = fsBlockNext(pFS, iBlk, &iNext);
    if( rc!=LSM_OK ) return rc;
    *piNew = fsFirstPageOnBlock(pFS, iNext);
    *piPrev = iBlk;
  }else{
    *piNew = iPrev+1;
    if( fsIsLast(pFS, *piNew) ){
      /* Allocate the next block here. */
      int iBlk;
      rc = lsmBlockAllocate(pFS->pDb, &iBlk);
      if( rc!=LSM_OK ) return rc;
      *piNext = iBlk;
    }
  }

  pSeg->nSize++;
  pSeg->iLastPg = *piNew;
  return LSM_OK;
}

/*
** If the page passed as an argument is dirty, update the database file
** (or mapping of the database file) with its current contents and mark
** the page as clean.
**
** Return LSM_OK if the operation is a success, or an LSM error code
................................................................................
      pPg->pHashNext = pFS->apHash[iHash];
      pFS->apHash[iHash] = pPg;

      pPg->pSeg->nSize += (sizeof(aSz) * 2) + pPg->nCompress;

    }else{
      i64 iOff;                   /* Offset to write within database file */

      if( pPg->iPg==0 ){
        /* No page number has been assigned yet. This occurs with pages used
        ** in the b-tree hierarchy.  */
        int iPrev = 0;
        int iNext = 0;
        int iHash;

        assert( pPg->pSeg->iFirst );
        assert( pPg->flags & PAGE_FREE );
        assert( (pPg->flags & PAGE_HASPREV)==0 );
        assert( pPg->nData==pFS->nPagesize-4 );

        rc = fsAppendPage(pFS, pPg->pSeg, &pPg->iPg, &iPrev, &iNext);
        if( rc!=LSM_OK ) return rc;

        iHash = fsHashKey(pFS->nHash, pPg->iPg);
        pPg->pHashNext = pFS->apHash[iHash];
        pFS->apHash[iHash] = pPg;

        if( iPrev ){
          assert( iNext==0 );
          memmove(&pPg->aData[4], pPg->aData, pPg->nData);
          lsmPutU32(pPg->aData, iPrev);
          pPg->flags |= PAGE_HASPREV;
          pPg->aData += 4;
        }else if( iNext ){
          assert( iPrev==0 );
          lsmPutU32(&pPg->aData[pPg->nData], iNext);
        }else{
          int nData = pPg->nData;
          pPg->nData += 4;
          lsmSortedExpandBtreePage(pPg, nData);
        }
      }

      iOff = (i64)pFS->nPagesize * (i64)(pPg->iPg-1);
      if( pFS->bUseMmap==0 ){
        u8 *aData = pPg->aData - (pPg->flags & PAGE_HASPREV);
        rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iOff, aData, pFS->nPagesize);
      }else if( pPg->flags & PAGE_FREE ){
        fsGrowMapping(pFS, iOff + pFS->nPagesize, &rc);
        if( rc==LSM_OK ){
          u8 *aTo = &((u8 *)(pFS->pMap))[iOff];
          u8 *aFrom = pPg->aData - (pPg->flags & PAGE_HASPREV);
          memcpy(aTo, aFrom, pFS->nPagesize);
          lsmFree(pFS->pEnv, aFrom);
          pPg->aData = aTo + (pPg->flags & PAGE_HASPREV);
          pPg->flags &= ~PAGE_FREE;
          fsPageAddToLru(pFS, pPg);
        }
      }
    }
    pPg->flags &= ~PAGE_DIRTY;
    pFS->nWrite++;

  **
  ** Given the context in which this function is called (as a result of an
  ** lsm_info(LSM_INFO_TREE_SIZE) request), neither of these are considered to
  ** be problems.
  */
  *pnNew = (int)p->root.nByte;
  if( p->iOldShmid ){
    if( p->iLogOff==lsmCheckpointLogOffset(pShm->aSnap1) ){
      *pnOld = 0;
    }else{
      *pnOld = (int)p->oldroot.nByte;
    }
  }else{
    *pnOld = 0;
  }

  **
  ** Given the context in which this function is called (as a result of an
  ** lsm_info(LSM_INFO_TREE_SIZE) request), neither of these are considered to
  ** be problems.
  */
  *pnNew = (int)p->root.nByte;
  if( p->iOldShmid ){
    if( p->iOldLog==lsmCheckpointLogOffset(pShm->aSnap1) ){
      *pnOld = 0;
    }else{
      *pnOld = (int)p->oldroot.nByte;
    }
  }else{
    *pnOld = 0;
  }

  Page **apHier = pMW->hier.apHier;
  int nHier = pMW->hier.nHier;

  pSeg = &pMW->pLevel->lhs;

  for(i=0; rc==LSM_OK && i<nHier; i++){
    Page *pNew = 0;
    rc = lsmFsSortedAppend(pDb->pFS, pDb->pWorker, pSeg, &pNew);
    assert( rc==LSM_OK );

    if( rc==LSM_OK ){
      u8 *a1; int n1;
      u8 *a2; int n2;

      a1 = fsPageData(pNew, &n1);
      a2 = fsPageData(apHier[i], &n2);

      assert( n1==n2 || n1+4==n2 || n2+4==n1 );

















      if( n1>=n2 ){
        /* If n1 (size of the new page) is equal to or greater than n2 (the
        ** size of the old page), then copy the data into the new page. If
        ** n1==n2, this could be done with a single memcpy(). However, 
        ** since sometimes n1>n2, the page content and footer must be copied 
        ** separately. */
        int nEntry = pageGetNRec(a2, n2);
................................................................................
      }else{
        lsmPutU16(&a1[SEGMENT_FLAGS_OFFSET(n1)], SEGMENT_BTREE_FLAG);
        lsmPutU16(&a1[SEGMENT_NRECORD_OFFSET(n1)], 0);
        lsmPutU64(&a1[SEGMENT_POINTER_OFFSET(n1)], 0);
        i = i - 1;
        lsmFsPageRelease(pNew);
      }

    }
  }

#ifdef LSM_DEBUG
  if( rc==LSM_OK ){
    for(i=0; i<nHier; i++) assert( lsmFsPageWritable(apHier[i]) );
  }
................................................................................
      nRec = pageGetNRec(aData, nData);
      nFree = SEGMENT_EOF(nData, nRec) - mergeWorkerPageOffset(aData, nData);
      if( nByte<=nFree ) break;

      /* Otherwise, this page is full. Set the right-hand-child pointer
      ** to iPtr and release it.  */
      lsmPutU64(&aData[SEGMENT_POINTER_OFFSET(nData)], iPtr);

      rc = lsmFsPagePersist(pOld);
      if( rc==LSM_OK ){
        iPtr = lsmFsPageNumber(pOld);
        lsmFsPageRelease(pOld);
      }
    }

    /* Allocate a new page for apHier[iLevel]. */
    p->apHier[iLevel] = 0;
    if( rc==LSM_OK ){
      rc = lsmFsSortedAppend(
          pDb->pFS, pDb->pWorker, pSeg, &p->apHier[iLevel]
      );
    }
    if( rc!=LSM_OK ) return rc;

    aData = fsPageData(p->apHier[iLevel], &nData);
    memset(aData, 0, nData);
    lsmPutU16(&aData[SEGMENT_FLAGS_OFFSET(nData)], SEGMENT_BTREE_FLAG);
................................................................................
){
  int rc = LSM_OK;                /* Return code */
  Page *pNext = 0;                /* New page appended to run */
  lsm_db *pDb = pMW->pDb;         /* Database handle */
  Segment *pSeg;                  /* Run to append to */

  pSeg = &pMW->pLevel->lhs;
  rc = lsmFsSortedAppend(pDb->pFS, pDb->pWorker, pSeg, &pNext);
  assert( rc!=LSM_OK || pSeg->iFirst>0 || pMW->pDb->compress.xCompress );

  if( rc==LSM_OK ){
    u8 *aData;                    /* Data buffer belonging to page pNext */
    int nData;                    /* Size of aData[] in bytes */

    rc = mergeWorkerPersistAndRelease(pMW);
................................................................................
    assert( rc!=LSM_OK || pDb->pWorker->freelist.nEntry==0 );
    lsmDbSnapshotSetLevel(pDb->pWorker, pNext);
    sortedFreeLevel(pDb->pEnv, pNew);
  }else{
    if( pDel ) pDel->iRoot = 0;

#if 0
    lsmSortedDumpStructure(pDb, pDb->pWorker, 0, 0, "new-toplevel");
#endif

    if( freelist.nEntry ){
      Freelist *p = &pDb->pWorker->freelist;
      lsmFree(pDb->pEnv, p->aEntry);
      memcpy(p, &freelist, sizeof(freelist));
      freelist.aEntry = 0;
................................................................................
      /* Clean up the MergeWorker object initialized above. If no error
      ** has occurred, invoke the work-hook to inform the application that
      ** the database structure has changed. */
      mergeWorkerShutdown(&mergeworker, &rc);
      if( rc==LSM_OK ) sortedInvokeWorkHook(pDb);

#if 0
      lsmSortedDumpStructure(pDb, pDb->pWorker, 0, 0, "work");
#endif
      assertBtreeOk(pDb, &pLevel->lhs);
      assertRunInOrder(pDb, &pLevel->lhs);

      /* If bFlush is true and the database is no longer considered "full",
      ** break out of the loop even if nRemaining is still greater than
      ** zero. The caller has an in-memory tree to flush to disk.  */
................................................................................
    u32 nUnsync;
    int nPgsz;

    lsmCheckpointSynced(pDb, 0, 0, &nSync);
    nUnsync = lsmCheckpointNWrite(pDb->pShmhdr->aSnap1, 0);
    nPgsz = lsmCheckpointPgsz(pDb->pShmhdr->aSnap1);

    nMax = LSM_MIN(nMax, (pDb->nAutockpt/nPgsz) - (nUnsync-nSync));
    if( nMax<nRem ){
      bCkpt = 1;
      nRem = LSM_MAX(nMax, 0);
    }
  }

  /* If there exists in-memory data ready to be flushed to disk, attempt
................................................................................
  }else{
    int rcdummy = LSM_BUSY;
    lsmFinishWork(pDb, 0, &rcdummy);
  }
  assert( pDb->pWorker==0 );

  if( rc==LSM_OK ){
    if( pnWrite ) *pnWrite = (nMax - nRem);
    if( pbCkpt ) *pbCkpt = (bCkpt && nRem<=0);
  }else{
    if( pnWrite ) *pnWrite = 0;
    if( pbCkpt ) *pbCkpt = 0;
  }

  return rc;
}

static int doLsmWork(lsm_db *pDb, int nMerge, int nPage, int *pnWrite){
  int rc;
................................................................................
void lsmSortedSaveTreeCursors(lsm_db *pDb){
  MultiCursor *pCsr;
  for(pCsr=pDb->pCsr; pCsr; pCsr=pCsr->pNext){
    lsmTreeCursorSave(pCsr->apTreeCsr[0]);
    lsmTreeCursorSave(pCsr->apTreeCsr[1]);
  }
}













#ifdef LSM_DEBUG_EXPENSIVE
static void assertRunInOrder(lsm_db *pDb, Segment *pSeg){
  Page *pPg = 0;
  Blob blob1 = {0, 0, 0, 0};
  Blob blob2 = {0, 0, 0, 0};

  Page **apHier = pMW->hier.apHier;
  int nHier = pMW->hier.nHier;

  pSeg = &pMW->pLevel->lhs;

  for(i=0; rc==LSM_OK && i<nHier; i++){
    Page *pNew = 0;
    rc = lsmFsSortedAppend(pDb->pFS, pDb->pWorker, pSeg, 1, &pNew);
    assert( rc==LSM_OK );

    if( rc==LSM_OK ){
      u8 *a1; int n1;
      u8 *a2; int n2;

      a1 = fsPageData(pNew, &n1);
      a2 = fsPageData(apHier[i], &n2);

      assert( n1==n2 || n1+4==n2 );

      if( n1==n2 ){
        memcpy(a1, a2, n2);
      }else{
        int nEntry = pageGetNRec(a2, n2);
        int iEof1 = SEGMENT_EOF(n1, nEntry);
        int iEof2 = SEGMENT_EOF(n2, nEntry);

        memcpy(a1, a2, iEof2 - 4);
        memcpy(&a1[iEof1], &a2[iEof2], n2 - iEof2);
      }

      lsmFsPageRelease(apHier[i]);
      apHier[i] = pNew;

#if 0
      assert( n1==n2 || n1+4==n2 || n2+4==n1 );
      if( n1>=n2 ){
        /* If n1 (size of the new page) is equal to or greater than n2 (the
        ** size of the old page), then copy the data into the new page. If
        ** n1==n2, this could be done with a single memcpy(). However, 
        ** since sometimes n1>n2, the page content and footer must be copied 
        ** separately. */
        int nEntry = pageGetNRec(a2, n2);
................................................................................
      }else{
        lsmPutU16(&a1[SEGMENT_FLAGS_OFFSET(n1)], SEGMENT_BTREE_FLAG);
        lsmPutU16(&a1[SEGMENT_NRECORD_OFFSET(n1)], 0);
        lsmPutU64(&a1[SEGMENT_POINTER_OFFSET(n1)], 0);
        i = i - 1;
        lsmFsPageRelease(pNew);
      }
#endif
    }
  }

#ifdef LSM_DEBUG
  if( rc==LSM_OK ){
    for(i=0; i<nHier; i++) assert( lsmFsPageWritable(apHier[i]) );
  }
................................................................................
      nRec = pageGetNRec(aData, nData);
      nFree = SEGMENT_EOF(nData, nRec) - mergeWorkerPageOffset(aData, nData);
      if( nByte<=nFree ) break;

      /* Otherwise, this page is full. Set the right-hand-child pointer
      ** to iPtr and release it.  */
      lsmPutU64(&aData[SEGMENT_POINTER_OFFSET(nData)], iPtr);
      assert( lsmFsPageNumber(pOld)==0 );
      rc = lsmFsPagePersist(pOld);
      if( rc==LSM_OK ){
        iPtr = lsmFsPageNumber(pOld);
        lsmFsPageRelease(pOld);
      }
    }

    /* Allocate a new page for apHier[iLevel]. */
    p->apHier[iLevel] = 0;
    if( rc==LSM_OK ){
      rc = lsmFsSortedAppend(
          pDb->pFS, pDb->pWorker, pSeg, 1, &p->apHier[iLevel]
      );
    }
    if( rc!=LSM_OK ) return rc;

    aData = fsPageData(p->apHier[iLevel], &nData);
    memset(aData, 0, nData);
    lsmPutU16(&aData[SEGMENT_FLAGS_OFFSET(nData)], SEGMENT_BTREE_FLAG);
................................................................................
){
  int rc = LSM_OK;                /* Return code */
  Page *pNext = 0;                /* New page appended to run */
  lsm_db *pDb = pMW->pDb;         /* Database handle */
  Segment *pSeg;                  /* Run to append to */

  pSeg = &pMW->pLevel->lhs;
  rc = lsmFsSortedAppend(pDb->pFS, pDb->pWorker, pSeg, 0, &pNext);
  assert( rc!=LSM_OK || pSeg->iFirst>0 || pMW->pDb->compress.xCompress );

  if( rc==LSM_OK ){
    u8 *aData;                    /* Data buffer belonging to page pNext */
    int nData;                    /* Size of aData[] in bytes */

    rc = mergeWorkerPersistAndRelease(pMW);
................................................................................
    assert( rc!=LSM_OK || pDb->pWorker->freelist.nEntry==0 );
    lsmDbSnapshotSetLevel(pDb->pWorker, pNext);
    sortedFreeLevel(pDb->pEnv, pNew);
  }else{
    if( pDel ) pDel->iRoot = 0;

#if 0
    lsmSortedDumpStructure(pDb, pDb->pWorker, 1, 0, "new-toplevel");
#endif

    if( freelist.nEntry ){
      Freelist *p = &pDb->pWorker->freelist;
      lsmFree(pDb->pEnv, p->aEntry);
      memcpy(p, &freelist, sizeof(freelist));
      freelist.aEntry = 0;
................................................................................
      /* Clean up the MergeWorker object initialized above. If no error
      ** has occurred, invoke the work-hook to inform the application that
      ** the database structure has changed. */
      mergeWorkerShutdown(&mergeworker, &rc);
      if( rc==LSM_OK ) sortedInvokeWorkHook(pDb);

#if 0
      lsmSortedDumpStructure(pDb, pDb->pWorker, 1, 0, "work");
#endif
      assertBtreeOk(pDb, &pLevel->lhs);
      assertRunInOrder(pDb, &pLevel->lhs);

      /* If bFlush is true and the database is no longer considered "full",
      ** break out of the loop even if nRemaining is still greater than
      ** zero. The caller has an in-memory tree to flush to disk.  */
................................................................................
    u32 nUnsync;
    int nPgsz;

    lsmCheckpointSynced(pDb, 0, 0, &nSync);
    nUnsync = lsmCheckpointNWrite(pDb->pShmhdr->aSnap1, 0);
    nPgsz = lsmCheckpointPgsz(pDb->pShmhdr->aSnap1);

    nMax = LSM_MIN(nMax, (pDb->nAutockpt/nPgsz) - (int)(nUnsync-nSync));
    if( nMax<nRem ){
      bCkpt = 1;
      nRem = LSM_MAX(nMax, 0);
    }
  }

  /* If there exists in-memory data ready to be flushed to disk, attempt
................................................................................
  }else{
    int rcdummy = LSM_BUSY;
    lsmFinishWork(pDb, 0, &rcdummy);
  }
  assert( pDb->pWorker==0 );

  if( rc==LSM_OK ){
    *pnWrite = (nMax - nRem);
    *pbCkpt = (bCkpt && nRem<=0);
  }else{
    *pnWrite = 0;
    *pbCkpt = 0;
  }

  return rc;
}

static int doLsmWork(lsm_db *pDb, int nMerge, int nPage, int *pnWrite){
  int rc;
................................................................................
void lsmSortedSaveTreeCursors(lsm_db *pDb){
  MultiCursor *pCsr;
  for(pCsr=pDb->pCsr; pCsr; pCsr=pCsr->pNext){
    lsmTreeCursorSave(pCsr->apTreeCsr[0]);
    lsmTreeCursorSave(pCsr->apTreeCsr[1]);
  }
}

void lsmSortedExpandBtreePage(Page *pPg, int nOrig){
  u8 *aData;
  int nData;
  int nEntry;
  int iHdr;

  aData = lsmFsPageData(pPg, &nData);
  nEntry = pageGetNRec(aData, nOrig);
  iHdr = SEGMENT_EOF(nOrig, nEntry);
  memmove(&aData[iHdr + (nData-nOrig)], &aData[iHdr], nOrig-iHdr);
}

#ifdef LSM_DEBUG_EXPENSIVE
static void assertRunInOrder(lsm_db *pDb, Segment *pSeg){
  Page *pPg = 0;
  Blob blob1 = {0, 0, 0, 0};
  Blob blob2 = {0, 0, 0, 0};

  append script $data3
  append script $data4

  append script "pause -1\n"
  exec_gnuplot_script $script $zPng
}

do_write_test x.png 600 50000 50000 20 {
  lsm-mt-1 "mmap=1 multi_proc=0 safety=0 threads=3 autowork=0 block_size=1M"
}







# lsm-mt    "mmap=1 multi_proc=0 threads=2 autowork=0 autocheckpoint=8192000"
# lsm-mt     "mmap=1 multi_proc=0 safety=1 threads=3 autowork=0"
# lsm-st     "mmap=1 multi_proc=0 safety=1 threads=1 autowork=1"
# lsm-mt     "mmap=1 multi_proc=0 safety=1 threads=3 autowork=0"
# lsm-mt     "mmap=1 multi_proc=0 safety=1 threads=3 autowork=0"
# LevelDB leveldb
# lsm-st     "mmap=1 multi_proc=0 safety=1 threads=1 autowork=1"
# LevelDB leveldb
# SQLite sqlite3

  append script $data3
  append script $data4

  append script "pause -1\n"
  exec_gnuplot_script $script $zPng
}

do_write_test x.png 100 50000 50000 20 {
  lsm safety=0
}


  #lsm "mmap=1 multi_proc=0 page_size=4096 block_size=2097152 autocheckpoint=4194000"
  #lsm-mt    "mmap=1 multi_proc=0 threads=2 autowork=0 autocheckpoint=4196000"

# lsm     "safety=1 multi_proc=0"

# lsm-mt    "mmap=1 multi_proc=0 threads=2 autowork=0 autocheckpoint=8192000"
# lsm-mt     "mmap=1 multi_proc=0 safety=1 threads=3 autowork=0"
# lsm-st     "mmap=1 multi_proc=0 safety=1 threads=1 autowork=1"
# lsm-mt     "mmap=1 multi_proc=0 safety=1 threads=3 autowork=0"
# lsm-mt     "mmap=1 multi_proc=0 safety=1 threads=3 autowork=0"
# LevelDB leveldb
# lsm-st     "mmap=1 multi_proc=0 safety=1 threads=1 autowork=1"
# LevelDB leveldb
# SQLite sqlite3

if any other client has written to the database since the current clients
read-transaction was opened, it will not be possible to upgrade to a
write-transaction.

<p>Write-transactions may be opened either implicitly or explicitly. If any
of the following functions are called to write to the database when there 
is no write-transaction open, then an implicit write-transaction is opened and
close (committed) within the function:

<ul>
  <li> lsm_insert()
  <li> lsm_delete()
  <li> lsm_delete_range()
</ul>

if any other client has written to the database since the current clients
read-transaction was opened, it will not be possible to upgrade to a
write-transaction.

<p>Write-transactions may be opened either implicitly or explicitly. If any
of the following functions are called to write to the database when there 
is no write-transaction open, then an implicit write-transaction is opened and
closed (committed) within the call:

<ul>
  <li> lsm_insert()
  <li> lsm_delete()
  <li> lsm_delete_range()
</ul>