#define ST_PAUSE   2
#define ST_FETCH   3
#define ST_SCAN    4
#define ST_NSCAN   5
#define ST_KEYSIZE 6
#define ST_VALSIZE 7

























int do_speed_test2(int nArg, char **azArg){
  struct Option {
    const char *zOpt;
    int eVal;
    int iDefault;
  } aOpt[] = {
    { "-repeat",  ST_REPEAT,    10},
................................................................................
    { "-pause",   ST_PAUSE,      0},
    { "-fetch",   ST_FETCH,      0},
    { "-scan",    ST_SCAN,       0},
    { "-nscan",   ST_NSCAN,      0},
    { "-keysize", ST_KEYSIZE,   12},
    { "-valsize", ST_VALSIZE,  100},
    { "-system",  -1,            0},

    {0, 0, 0}
  };
  int i;
  int aParam[8];
  int rc = 0;

  TestDb *pDb;
................................................................................
    if( aOpt[i].zOpt ) aParam[aOpt[i].eVal] = aOpt[i].iDefault;
  }

  /* Process the command line switches. */
  for(i=0; i<nArg; i+=2){
    int iSel;
    rc = testArgSelect(aOpt, "switch", azArg[i], &iSel);

    if( rc ) return rc;





    if( i+1==nArg ){
      testPrintError("option %s requires an argument\n", aOpt[iSel].zOpt);
      return 1;
    }
    if( aOpt[iSel].eVal>=0 ){
      aParam[aOpt[iSel].eVal] = atoi(azArg[i+1]);
    }else{

#define ST_PAUSE   2
#define ST_FETCH   3
#define ST_SCAN    4
#define ST_NSCAN   5
#define ST_KEYSIZE 6
#define ST_VALSIZE 7


static void print_speed_test_help(){
  printf(
"\n"
"Repeat the following $repeat times:\n"
"  1. Insert $write key-value pairs. One transaction for each write op.\n"
"  2. Pause for $pause ms.\n"
"  3. Perform $fetch queries on the database.\n"
"\n"
"  Keys are $keysize bytes in size. Values are $valsize bytes in size\n"
"  Both keys and values are pseudo-randomly generated\n"
"\n"
"Options are:\n"
"  -repeat  $repeat                 (default value 10)\n"
"  -write   $write                  (default value 10000)\n"
"  -pause   $pause                  (default value 0)\n"
"  -fetch   $fetch                  (default value 0)\n"
"  -keysize $keysize                (default value 12)\n"
"  -valsize $valsize                (default value 100)\n"
"  -system  $system                 (default value \"lsm\"\n"
"\n"
);
}

int do_speed_test2(int nArg, char **azArg){
  struct Option {
    const char *zOpt;
    int eVal;
    int iDefault;
  } aOpt[] = {
    { "-repeat",  ST_REPEAT,    10},
................................................................................
    { "-pause",   ST_PAUSE,      0},
    { "-fetch",   ST_FETCH,      0},
    { "-scan",    ST_SCAN,       0},
    { "-nscan",   ST_NSCAN,      0},
    { "-keysize", ST_KEYSIZE,   12},
    { "-valsize", ST_VALSIZE,  100},
    { "-system",  -1,            0},
    { "help",     -2,            0},
    {0, 0, 0}
  };
  int i;
  int aParam[8];
  int rc = 0;

  TestDb *pDb;
................................................................................
    if( aOpt[i].zOpt ) aParam[aOpt[i].eVal] = aOpt[i].iDefault;
  }

  /* Process the command line switches. */
  for(i=0; i<nArg; i+=2){
    int iSel;
    rc = testArgSelect(aOpt, "switch", azArg[i], &iSel);
    if( rc ){
      return rc;
    }
    if( aOpt[iSel].eVal==-2 ){
      print_speed_test_help();
      return 0;
    }
    if( i+1==nArg ){
      testPrintError("option %s requires an argument\n", aOpt[iSel].zOpt);
      return 1;
    }
    if( aOpt[iSel].eVal>=0 ){
      aParam[aOpt[iSel].eVal] = atoi(azArg[i+1]);
    }else{

static void xWorkHook(lsm_db *db, void *pArg){
  LsmDb *p = (LsmDb *)pArg;
  if( p->xWork ) p->xWork(db, p->pWorkCtx);
}

#define TEST_NO_RECOVERY -1


int test_lsm_config_str(
  LsmDb *pLsm,
  lsm_db *db, 
  int bWorker,
  const char *zStr

){
  struct CfgParam {
    const char *zParam;
    int bWorker;
    int eParam;
  } aParam[] = {
    { "write_buffer",     0, LSM_CONFIG_WRITE_BUFFER },
................................................................................
    { "mmap",             0, LSM_CONFIG_MMAP },
    { "use_log",          0, LSM_CONFIG_USE_LOG },
    { "nmerge",           0, LSM_CONFIG_NMERGE },
    { "max_freelist",     0, LSM_CONFIG_MAX_FREELIST },
    { "multi_proc",       0, LSM_CONFIG_MULTIPLE_PROCESSES },
    { "worker_nmerge",    1, LSM_CONFIG_NMERGE },
    { "test_no_recovery", 0, TEST_NO_RECOVERY },

    { 0, 0 }
  };
  const char *z = zStr;


  assert( db );
  while( z[0] ){
    const char *zStart;

    /* Skip whitespace */
    while( *z==' ' ) z++;
................................................................................
        }
      }else{
        if( pLsm ){
          switch( eParam ){
            case TEST_NO_RECOVERY:
              pLsm->bNoRecovery = iVal;
              break;



          }
        }
      }
    }else if( z!=zStart ){
      goto syntax_error;
    }
  }


  return 0;
 syntax_error:
  testPrintError("syntax error at: \"%s\"\n", z);
  return 1;
}

int tdb_lsm_config_str(TestDb *pDb, const char *zStr){
  int rc = 0;
  if( tdb_lsm(pDb) ){
    int i;
    LsmDb *pLsm = (LsmDb *)pDb;

    rc = test_lsm_config_str(pLsm, pLsm->db, 0, zStr);
#ifdef LSM_MUTEX_PTHREADS
    for(i=0; rc==0 && i<pLsm->nWorker; i++){
      rc = test_lsm_config_str(0, pLsm->aWorker[i].pWorker, 1, zStr);
    }
#endif
  }
  return rc;
}



static int testLsmOpen(
  const char *zCfg,
  const char *zFilename, 
  int bClear, 
  TestDb **ppDb
){
................................................................................
  pDb->env.xShmBarrier = testEnvShmBarrier;
  pDb->env.xShmMap = testEnvShmMap;
  pDb->env.xShmUnmap = testEnvShmUnmap;
  pDb->env.xSleep = testEnvSleep;

  rc = lsm_new(&pDb->env, &pDb->db);
  if( rc==LSM_OK ){

    lsm_config_log(pDb->db, xLog, 0);
    lsm_config_work_hook(pDb->db, xWorkHook, (void *)pDb);
    rc = tdb_lsm_config_str((TestDb *)pDb, zCfg);


    if( rc==LSM_OK ) rc = lsm_open(pDb->db, zFilename);







    if( rc!=LSM_OK ){
      test_lsm_close((TestDb *)pDb);
      pDb = 0;
    }
  }

  *ppDb = (TestDb *)pDb;
................................................................................
  while( (pWorker = p->pWorker) ){
    int nWrite = 0;
    int rc;

    /* Do some work. If an error occurs, exit. */
    pthread_mutex_unlock(&p->worker_mutex);
    rc = lsm_work(pWorker, p->lsm_work_flags, p->lsm_work_npage, &nWrite);

    pthread_mutex_lock(&p->worker_mutex);
    if( rc!=LSM_OK ){
      p->worker_rc = rc;
      break;
    }

    /* If the call to lsm_work() indicates that there is nothing more
    ** to do at this point, wait on the condition variable. The thread will
    ** wake up when it is signaled either because the client thread has
................................................................................
      if( p->pWorker && p->bDoWork==0 ){
        pthread_cond_wait(&p->worker_cond, &p->worker_mutex);
      }
      p->bDoWork = 0;
    }
  }
  pthread_mutex_unlock(&p->worker_mutex);

  
  return 0;
}


/*
** Signal worker thread iWorker that there may be work to do.
................................................................................
static void mt_client_work_hook(lsm_db *db, void *pArg){
  LsmDb *pDb = (LsmDb *)pArg;     /* LsmDb database handle */
  int i;                          /* Iterator variable */

  /* Invoke the user level work-hook, if any. */
  if( pDb->xWork ) pDb->xWork(db, pDb->pWorkCtx);


  /* Signal each worker thread */
  for(i=0; i<pDb->nWorker; i++){
    mt_signal_worker(pDb, i);
  }
}

static void mt_worker_work_hook(lsm_db *db, void *pArg){
................................................................................
  /* Kick off the worker thread. */
  if( rc==0 ) rc = pthread_cond_init(&p->worker_cond, 0);
  if( rc==0 ) rc = pthread_mutex_init(&p->worker_mutex, 0);
  if( rc==0 ) rc = pthread_create(&p->worker_thread, 0, worker_main, (void *)p);

  return rc;
}




































static int test_lsm_mt(
  const char *zFilename,          /* File to open */
  int nWorker,                    /* Either 1 or 2, for worker threads */
  int bClear,                     /* True to delete any existing db */
  TestDb **ppDb                   /* OUT: TestDb database handle */
){

static void xWorkHook(lsm_db *db, void *pArg){
  LsmDb *p = (LsmDb *)pArg;
  if( p->xWork ) p->xWork(db, p->pWorkCtx);
}

#define TEST_NO_RECOVERY -1
#define TEST_THREADS     -2

static int test_lsm_config_str(
  LsmDb *pLsm,
  lsm_db *db, 
  int bWorker,
  const char *zStr,
  int *pnThread
){
  struct CfgParam {
    const char *zParam;
    int bWorker;
    int eParam;
  } aParam[] = {
    { "write_buffer",     0, LSM_CONFIG_WRITE_BUFFER },
................................................................................
    { "mmap",             0, LSM_CONFIG_MMAP },
    { "use_log",          0, LSM_CONFIG_USE_LOG },
    { "nmerge",           0, LSM_CONFIG_NMERGE },
    { "max_freelist",     0, LSM_CONFIG_MAX_FREELIST },
    { "multi_proc",       0, LSM_CONFIG_MULTIPLE_PROCESSES },
    { "worker_nmerge",    1, LSM_CONFIG_NMERGE },
    { "test_no_recovery", 0, TEST_NO_RECOVERY },
    { "threads",          0, TEST_THREADS },
    { 0, 0 }
  };
  const char *z = zStr;
  int nThread = 1;

  assert( db );
  while( z[0] ){
    const char *zStart;

    /* Skip whitespace */
    while( *z==' ' ) z++;
................................................................................
        }
      }else{
        if( pLsm ){
          switch( eParam ){
            case TEST_NO_RECOVERY:
              pLsm->bNoRecovery = iVal;
              break;
            case TEST_THREADS:
              nThread = iVal;
              break;
          }
        }
      }
    }else if( z!=zStart ){
      goto syntax_error;
    }
  }

  if( pnThread ) *pnThread = nThread;
  return 0;
 syntax_error:
  testPrintError("syntax error at: \"%s\"\n", z);
  return 1;
}

int tdb_lsm_config_str(TestDb *pDb, const char *zStr){
  int rc = 0;
  if( tdb_lsm(pDb) ){
    int i;
    LsmDb *pLsm = (LsmDb *)pDb;

    rc = test_lsm_config_str(pLsm, pLsm->db, 0, zStr, 0);
#ifdef LSM_MUTEX_PTHREADS
    for(i=0; rc==0 && i<pLsm->nWorker; i++){
      rc = test_lsm_config_str(0, pLsm->aWorker[i].pWorker, 1, zStr, 0);
    }
#endif
  }
  return rc;
}

static int testLsmStartWorkers(LsmDb *, int, const char *, const char *);

static int testLsmOpen(
  const char *zCfg,
  const char *zFilename, 
  int bClear, 
  TestDb **ppDb
){
................................................................................
  pDb->env.xShmBarrier = testEnvShmBarrier;
  pDb->env.xShmMap = testEnvShmMap;
  pDb->env.xShmUnmap = testEnvShmUnmap;
  pDb->env.xSleep = testEnvSleep;

  rc = lsm_new(&pDb->env, &pDb->db);
  if( rc==LSM_OK ){
    int nThread = 1;
    lsm_config_log(pDb->db, xLog, 0);
    lsm_config_work_hook(pDb->db, xWorkHook, (void *)pDb);


    rc = test_lsm_config_str(pDb, pDb->db, 0, zCfg, &nThread);
    if( rc==LSM_OK ) rc = lsm_open(pDb->db, zFilename);

#ifdef LSM_MUTEX_PTHREADS
    if( rc==LSM_OK && (nThread==2 || nThread==3) ){
      testLsmStartWorkers(pDb, nThread-1, zFilename, zCfg);
    }
#endif

    if( rc!=LSM_OK ){
      test_lsm_close((TestDb *)pDb);
      pDb = 0;
    }
  }

  *ppDb = (TestDb *)pDb;
................................................................................
  while( (pWorker = p->pWorker) ){
    int nWrite = 0;
    int rc;

    /* Do some work. If an error occurs, exit. */
    pthread_mutex_unlock(&p->worker_mutex);
    rc = lsm_work(pWorker, p->lsm_work_flags, p->lsm_work_npage, &nWrite);
    printf("# worked %d units\n", nWrite);
    pthread_mutex_lock(&p->worker_mutex);
    if( rc!=LSM_OK && rc!=LSM_BUSY ){
      p->worker_rc = rc;
      break;
    }

    /* If the call to lsm_work() indicates that there is nothing more
    ** to do at this point, wait on the condition variable. The thread will
    ** wake up when it is signaled either because the client thread has
................................................................................
      if( p->pWorker && p->bDoWork==0 ){
        pthread_cond_wait(&p->worker_cond, &p->worker_mutex);
      }
      p->bDoWork = 0;
    }
  }
  pthread_mutex_unlock(&p->worker_mutex);
  printf("# worker EXIT\n");
  
  return 0;
}


/*
** Signal worker thread iWorker that there may be work to do.
................................................................................
static void mt_client_work_hook(lsm_db *db, void *pArg){
  LsmDb *pDb = (LsmDb *)pArg;     /* LsmDb database handle */
  int i;                          /* Iterator variable */

  /* Invoke the user level work-hook, if any. */
  if( pDb->xWork ) pDb->xWork(db, pDb->pWorkCtx);

  printf("# signalling worker threads\n");
  /* Signal each worker thread */
  for(i=0; i<pDb->nWorker; i++){
    mt_signal_worker(pDb, i);
  }
}

static void mt_worker_work_hook(lsm_db *db, void *pArg){
................................................................................
  /* Kick off the worker thread. */
  if( rc==0 ) rc = pthread_cond_init(&p->worker_cond, 0);
  if( rc==0 ) rc = pthread_mutex_init(&p->worker_mutex, 0);
  if( rc==0 ) rc = pthread_create(&p->worker_thread, 0, worker_main, (void *)p);

  return rc;
}


static int testLsmStartWorkers(
  LsmDb *pDb, int nWorker, const char *zFilename, const char *zCfg
){
  int rc;
  int bAutowork = 0;
  assert( nWorker==1 || nWorker==2 );

#if 0
  /* Turn off auto-work and configure a work-hook on the client connection. */
  lsm_config(pDb->db, LSM_CONFIG_AUTOWORK, &bAutowork);
#endif
  lsm_config_work_hook(pDb->db, mt_client_work_hook, (void *)pDb);

  pDb->aWorker = (LsmWorker *)testMalloc(sizeof(LsmWorker) * nWorker);
  memset(pDb->aWorker, 0, sizeof(LsmWorker) * nWorker);
  pDb->nWorker = nWorker;

  rc = mt_start_worker(
      pDb, 0, zFilename, LSM_WORK_CHECKPOINT|LSM_WORK_FLUSH, 512
  );
#if 0
  rc = mt_start_worker(pDb, 0, zFilename, LSM_WORK_CHECKPOINT, 
      nWorker==1 ? 512 : 0
  );
#endif

  if( rc==0 && nWorker==2 ){
    rc = mt_start_worker(pDb, 1, zFilename, 0, 512);
  }

  return rc;
}


static int test_lsm_mt(
  const char *zFilename,          /* File to open */
  int nWorker,                    /* Either 1 or 2, for worker threads */
  int bClear,                     /* True to delete any existing db */
  TestDb **ppDb                   /* OUT: TestDb database handle */
){

typedef struct FileSystem FileSystem;
typedef struct Level Level;
typedef struct LogMark LogMark;
typedef struct LogRegion LogRegion;
typedef struct LogWriter LogWriter;
typedef struct LsmString LsmString;
typedef struct Mempool Mempool;


typedef struct MetaPage MetaPage;
typedef struct MultiCursor MultiCursor;
typedef struct Page Page;
typedef struct Segment Segment;
typedef struct SegmentMerger SegmentMerger;



typedef struct Snapshot Snapshot;
typedef struct TransMark TransMark;
typedef struct Tree Tree;
typedef struct TreeMark TreeMark;
typedef struct TreeVersion TreeVersion;
typedef struct TreeCursor TreeCursor;
typedef struct Merge Merge;
typedef struct MergeInput MergeInput;

typedef struct TreeHeader TreeHeader;
typedef struct ShmHeader ShmHeader;
typedef struct ShmChunk ShmChunk;
typedef struct ShmReader ShmReader;

typedef unsigned char u8;
typedef unsigned short int u16;
typedef unsigned int u32;
typedef lsm_i64 i64;
typedef unsigned long long int u64;

................................................................................
struct DbLog {
  u32 cksum0;                     /* Checksum 0 at offset iOff */
  u32 cksum1;                     /* Checksum 1 at offset iOff */
  i64 iSnapshotId;                /* Log space has been reclaimed to this ss */
  LogRegion aRegion[3];           /* Log file regions (see docs in lsm_log.c) */
};







/*
** Tree header structure. 
*/
struct TreeHeader {
  u32 iUsedShmid;                 /* Id of first shm chunk used by this tree */
  u32 iNextShmid;                 /* Shm-id of next chunk allocated */
  u32 iFirst;                     /* Chunk number of smallest shm-id */
  u32 iTransId;                   /* Current transaction id */
  u32 nChunk;                     /* Number of chunks in shared-memory file */
  u32 iRoot;                      /* Offset of root node in shm file */
  u32 nHeight;                    /* Current height of tree structure */

  u32 iWrite;                     /* Write offset in shm file */
  u32 nByte;                      /* Size of current tree structure in bytes */





  DbLog log;                      /* Current layout of log file */ 
  u32 aCksum[2];                  /* Checksums 1 and 2. */
};

/*
** Database handle structure.
**
................................................................................
** to read or write a database file on disk. See the description of struct
** Database below for futher details.
*/
struct Snapshot {
  Database *pDatabase;            /* Database this snapshot belongs to */
  Level *pLevel;                  /* Pointer to level 0 of snapshot (or NULL) */
  i64 iId;                        /* Snapshot id */


  /* Used by worker snapshots only */
  int nBlock;                     /* Number of blocks in database file */
  u32 aiAppend[LSM_APPLIST_SZ];   /* Append point list */
  Freelist freelist;              /* Free block list */
  int nFreelistOvfl;              /* Number of extra free-list entries in LSM */
};
................................................................................
*/
int lsmTreeNew(lsm_env *, int (*)(void *, int, void *, int), Tree **ppTree);
void lsmTreeRelease(lsm_env *, Tree *);
void lsmTreeClear(lsm_db *);
int lsmTreeInit(lsm_db *);
int lsmTreeRepair(lsm_db *);





int lsmTreeSize(lsm_db *);
int lsmTreeEndTransaction(lsm_db *pDb, int bCommit);
int lsmTreeBeginTransaction(lsm_db *pDb);
int lsmTreeLoadHeader(lsm_db *pDb, int *);
int lsmTreeLoadHeaderOk(lsm_db *, int);

int lsmTreeInsert(lsm_db *pDb, void *pKey, int nKey, void *pVal, int nVal);
void lsmTreeRollback(lsm_db *pDb, TreeMark *pMark);
void lsmTreeMark(lsm_db *pDb, TreeMark *pMark);

int lsmTreeCursorNew(lsm_db *pDb, TreeCursor **);
void lsmTreeCursorDestroy(TreeCursor *);

int lsmTreeCursorSeek(TreeCursor *pCsr, void *pKey, int nKey, int *pRes);
int lsmTreeCursorNext(TreeCursor *pCsr);
int lsmTreeCursorPrev(TreeCursor *pCsr);
int lsmTreeCursorEnd(TreeCursor *pCsr, int bLast);
void lsmTreeCursorReset(TreeCursor *pCsr);

typedef struct FileSystem FileSystem;
typedef struct Level Level;
typedef struct LogMark LogMark;
typedef struct LogRegion LogRegion;
typedef struct LogWriter LogWriter;
typedef struct LsmString LsmString;
typedef struct Mempool Mempool;
typedef struct Merge Merge;
typedef struct MergeInput MergeInput;
typedef struct MetaPage MetaPage;
typedef struct MultiCursor MultiCursor;
typedef struct Page Page;
typedef struct Segment Segment;
typedef struct SegmentMerger SegmentMerger;
typedef struct ShmChunk ShmChunk;
typedef struct ShmHeader ShmHeader;
typedef struct ShmReader ShmReader;
typedef struct Snapshot Snapshot;
typedef struct TransMark TransMark;
typedef struct Tree Tree;


typedef struct TreeCursor TreeCursor;



typedef struct TreeHeader TreeHeader;
typedef struct TreeMark TreeMark;
typedef struct TreeRoot TreeRoot;


typedef unsigned char u8;
typedef unsigned short int u16;
typedef unsigned int u32;
typedef lsm_i64 i64;
typedef unsigned long long int u64;

................................................................................
struct DbLog {
  u32 cksum0;                     /* Checksum 0 at offset iOff */
  u32 cksum1;                     /* Checksum 1 at offset iOff */
  i64 iSnapshotId;                /* Log space has been reclaimed to this ss */
  LogRegion aRegion[3];           /* Log file regions (see docs in lsm_log.c) */
};

struct TreeRoot {
  u32 iRoot;
  u32 nHeight;
  u32 iTransId;
};

/*
** Tree header structure. 
*/
struct TreeHeader {
  u32 iUsedShmid;                 /* Id of first shm chunk used by this tree */
  u32 iNextShmid;                 /* Shm-id of next chunk allocated */
  u32 iFirst;                     /* Chunk number of smallest shm-id */

  u32 nChunk;                     /* Number of chunks in shared-memory file */


  TreeRoot root;                  /* Root and height of current tree */
  u32 iWrite;                     /* Write offset in shm file */
  u32 nByte;                      /* Size of current tree structure in bytes */
  TreeRoot oldroot;               /* Root and height of the previous tree */
  u32 iOldShmid;                  /* Last shm-id used by previous tree */
  i64 iOldLog;                    /* Log offset associated with old tree */
  u32 oldcksum0;
  u32 oldcksum1;
  DbLog log;                      /* Current layout of log file */ 
  u32 aCksum[2];                  /* Checksums 1 and 2. */
};

/*
** Database handle structure.
**
................................................................................
** to read or write a database file on disk. See the description of struct
** Database below for futher details.
*/
struct Snapshot {
  Database *pDatabase;            /* Database this snapshot belongs to */
  Level *pLevel;                  /* Pointer to level 0 of snapshot (or NULL) */
  i64 iId;                        /* Snapshot id */
  i64 iLogOff;                    /* Log file offset */

  /* Used by worker snapshots only */
  int nBlock;                     /* Number of blocks in database file */
  u32 aiAppend[LSM_APPLIST_SZ];   /* Append point list */
  Freelist freelist;              /* Free block list */
  int nFreelistOvfl;              /* Number of extra free-list entries in LSM */
};
................................................................................
*/
int lsmTreeNew(lsm_env *, int (*)(void *, int, void *, int), Tree **ppTree);
void lsmTreeRelease(lsm_env *, Tree *);
void lsmTreeClear(lsm_db *);
int lsmTreeInit(lsm_db *);
int lsmTreeRepair(lsm_db *);

void lsmTreeMakeOld(lsm_db *pDb, int *pnFlush);
void lsmTreeDiscardOld(lsm_db *pDb);
int lsmTreeHasOld(lsm_db *pDb);

int lsmTreeSize(lsm_db *);
int lsmTreeEndTransaction(lsm_db *pDb, int bCommit);

int lsmTreeLoadHeader(lsm_db *pDb, int *);
int lsmTreeLoadHeaderOk(lsm_db *, int);

int lsmTreeInsert(lsm_db *pDb, void *pKey, int nKey, void *pVal, int nVal);
void lsmTreeRollback(lsm_db *pDb, TreeMark *pMark);
void lsmTreeMark(lsm_db *pDb, TreeMark *pMark);

int lsmTreeCursorNew(lsm_db *pDb, int, TreeCursor **);
void lsmTreeCursorDestroy(TreeCursor *);

int lsmTreeCursorSeek(TreeCursor *pCsr, void *pKey, int nKey, int *pRes);
int lsmTreeCursorNext(TreeCursor *pCsr);
int lsmTreeCursorPrev(TreeCursor *pCsr);
int lsmTreeCursorEnd(TreeCursor *pCsr, int bLast);
void lsmTreeCursorReset(TreeCursor *pCsr);

**     5. The block size.
**     6. The number of levels.
**     7. The nominal database page size.
**     8. Flag indicating if there exists a FREELIST record in the database.
**
**   Log pointer:
**
**     4 integers (2 for a 64-bit offset and 2 for a 64-bit checksum). See 




**     ckptExportLog() and ckptImportLog().
**
**   Append points:
**
**     4 integers. See ckptExportAppendlist().
**
**   For each level in the database, a level record. Formatted as follows:
**
................................................................................
  int *piOut, 
  int *pRc
){
  int iOut = *piOut;

  assert( iOut==CKPT_HDR_LO_MSW );

  if( bFlush ){
    DbLog *pLog = &pDb->treehdr.log;
    i64 iOff = pLog->aRegion[2].iEnd;
    ckptSetValue(p, iOut++, (iOff >> 32) & 0xFFFFFFFF, pRc);
    ckptSetValue(p, iOut++, (iOff & 0xFFFFFFFF), pRc);
    ckptSetValue(p, iOut++, pLog->cksum0, pRc);
    ckptSetValue(p, iOut++, pLog->cksum1, pRc);
  }else{
    for(; iOut<=CKPT_HDR_LO_CKSUM2; iOut++){
      ckptSetValue(p, iOut, pDb->pShmhdr->aSnap2[iOut], pRc);
    }
  }

  *piOut = iOut;
................................................................................
    int nCopy;
    int nLevel = (int)aCkpt[CKPT_HDR_NLEVEL];
    int iIn = CKPT_HDR_SIZE + CKPT_APPENDLIST_SIZE + CKPT_LOGPTR_SIZE;

    pNew->iId = lsmCheckpointId(aCkpt, 0);
    pNew->nBlock = aCkpt[CKPT_HDR_NBLOCK];
    rc = ckptLoadLevels(pDb, aCkpt, &iIn, nLevel, &pNew->pLevel);


    /* Make a copy of the append-list */
    nCopy = sizeof(u32) * LSM_APPLIST_SZ;
    memcpy(pNew->aiAppend, &aCkpt[CKPT_HDR_SIZE+CKPT_LOGPTR_SIZE], nCopy);

    /* Copy the free-list */
    if( bInclFreelist ){

**     5. The block size.
**     6. The number of levels.
**     7. The nominal database page size.
**     8. Flag indicating if there exists a FREELIST record in the database.
**
**   Log pointer:
**
**     1. The log offset MSW.
**     2. The log offset LSW.
**     3. Log checksum 0.
**     4. Log checksum 1.
**
**     See ckptExportLog() and ckptImportLog().
**
**   Append points:
**
**     4 integers. See ckptExportAppendlist().
**
**   For each level in the database, a level record. Formatted as follows:
**
................................................................................
  int *piOut, 
  int *pRc
){
  int iOut = *piOut;

  assert( iOut==CKPT_HDR_LO_MSW );

  if( bFlush && pDb->treehdr.iOldShmid ){
    i64 iOff = pDb->treehdr.iOldLog;

    ckptSetValue(p, iOut++, (iOff >> 32) & 0xFFFFFFFF, pRc);
    ckptSetValue(p, iOut++, (iOff & 0xFFFFFFFF), pRc);
    ckptSetValue(p, iOut++, pDb->treehdr.oldcksum0, pRc);
    ckptSetValue(p, iOut++, pDb->treehdr.oldcksum1, pRc);
  }else{
    for(; iOut<=CKPT_HDR_LO_CKSUM2; iOut++){
      ckptSetValue(p, iOut, pDb->pShmhdr->aSnap2[iOut], pRc);
    }
  }

  *piOut = iOut;
................................................................................
    int nCopy;
    int nLevel = (int)aCkpt[CKPT_HDR_NLEVEL];
    int iIn = CKPT_HDR_SIZE + CKPT_APPENDLIST_SIZE + CKPT_LOGPTR_SIZE;

    pNew->iId = lsmCheckpointId(aCkpt, 0);
    pNew->nBlock = aCkpt[CKPT_HDR_NBLOCK];
    rc = ckptLoadLevels(pDb, aCkpt, &iIn, nLevel, &pNew->pLevel);
    pNew->iLogOff = lsmCheckpointLogOffset(aCkpt);

    /* Make a copy of the append-list */
    nCopy = sizeof(u32) * LSM_APPLIST_SZ;
    memcpy(pNew->aiAppend, &aCkpt[CKPT_HDR_SIZE+CKPT_LOGPTR_SIZE], nCopy);

    /* Copy the free-list */
    if( bInclFreelist ){

  }

  /* Write the contents of the in-memory tree into the database file and 
  ** update the worker snapshot accordingly. Then flush the contents of 
  ** the db file to disk too. No calls to fsync() are made here - just 
  ** write().  */
  if( rc==LSM_OK ) rc = lsmSortedFlushTree(pDb, &nOvfl);
  if( rc==LSM_OK ) lsmTreeClear(pDb);

  lsmFinishWork(pDb, 1, nOvfl, &rc);

  /* Restore the position of any open cursors */
  if( rc==LSM_OK && pDb->pCsr ){
    lsmFreeSnapshot(pDb->pEnv, pDb->pClient);
    pDb->pClient = 0;
    rc = lsmCheckpointLoad(pDb, 0);
................................................................................

    nBefore = lsmTreeSize(pDb);
    rc = lsmTreeInsert(pDb, (void *)pKey, nKey, (void *)pVal, nVal);
    nAfter = lsmTreeSize(pDb);
    nDiff = (nAfter/nQuant) - (nBefore/nQuant);
    if( rc==LSM_OK && pDb->bAutowork && nDiff!=0 ){
      rc = dbAutoWork(pDb, nDiff * LSM_AUTOWORK_QUANT);

    }
  }

  /* If a transaction was opened at the start of this function, commit it. 
  ** Or, if an error has occurred, roll it back.
  */
  if( bCommit ){
................................................................................
    }
  }

  return rc;
}

int lsm_commit(lsm_db *pDb, int iLevel){
  int bFlush = 0;
  int rc = LSM_OK;

  assert_db_state( pDb );

  /* A value less than zero means close the innermost nested transaction. */
  if( iLevel<0 ) iLevel = LSM_MAX(0, pDb->nTransOpen - 1);

  if( iLevel<pDb->nTransOpen ){
    if( iLevel==0 ){

      /* Commit the transaction to disk. */
      if( lsmTreeSize(pDb)>pDb->nTreeLimit ){
        lsmTreeEndTransaction(pDb, 1);
        bFlush = 1;
        rc = lsmFlushToDisk(pDb);
      }
      if( rc==LSM_OK ) rc = lsmLogCommit(pDb);
      if( rc==LSM_OK && pDb->eSafety==LSM_SAFETY_FULL ){
        rc = lsmFsSyncLog(pDb->pFS);
      }




      lsmFinishWriteTrans(pDb, (rc==LSM_OK));
    }
    pDb->nTransOpen = iLevel;
  }

  dbReleaseClientSnapshot(pDb);

















  if( pDb->bAutowork && bFlush && rc==LSM_OK ){
    rc = lsmCheckpointWrite(pDb);
  }



  return rc;
}

int lsm_rollback(lsm_db *pDb, int iLevel){
  int rc = LSM_OK;
  assert_db_state( pDb );

  }

  /* Write the contents of the in-memory tree into the database file and 
  ** update the worker snapshot accordingly. Then flush the contents of 
  ** the db file to disk too. No calls to fsync() are made here - just 
  ** write().  */
  if( rc==LSM_OK ) rc = lsmSortedFlushTree(pDb, &nOvfl);


  lsmFinishWork(pDb, 1, nOvfl, &rc);

  /* Restore the position of any open cursors */
  if( rc==LSM_OK && pDb->pCsr ){
    lsmFreeSnapshot(pDb->pEnv, pDb->pClient);
    pDb->pClient = 0;
    rc = lsmCheckpointLoad(pDb, 0);
................................................................................

    nBefore = lsmTreeSize(pDb);
    rc = lsmTreeInsert(pDb, (void *)pKey, nKey, (void *)pVal, nVal);
    nAfter = lsmTreeSize(pDb);
    nDiff = (nAfter/nQuant) - (nBefore/nQuant);
    if( rc==LSM_OK && pDb->bAutowork && nDiff!=0 ){
      rc = dbAutoWork(pDb, nDiff * LSM_AUTOWORK_QUANT);
      if( rc==LSM_BUSY ) rc = LSM_OK;
    }
  }

  /* If a transaction was opened at the start of this function, commit it. 
  ** Or, if an error has occurred, roll it back.
  */
  if( bCommit ){
................................................................................
    }
  }

  return rc;
}

int lsm_commit(lsm_db *pDb, int iLevel){
  int nFlush = 0;                 /* Number of flushable trees in memory */
  int rc = LSM_OK;

  assert_db_state( pDb );

  /* A value less than zero means close the innermost nested transaction. */
  if( iLevel<0 ) iLevel = LSM_MAX(0, pDb->nTransOpen - 1);

  if( iLevel<pDb->nTransOpen ){
    if( iLevel==0 ){

      /* Commit the transaction to disk. */





      if( rc==LSM_OK ) rc = lsmLogCommit(pDb);
      if( rc==LSM_OK && pDb->eSafety==LSM_SAFETY_FULL ){
        rc = lsmFsSyncLog(pDb->pFS);
      }

      if( lsmTreeSize(pDb)>pDb->nTreeLimit ){
        lsmTreeMakeOld(pDb, &nFlush);
      }
      lsmFinishWriteTrans(pDb, (rc==LSM_OK));
    }
    pDb->nTransOpen = iLevel;

  }
  dbReleaseClientSnapshot(pDb);

  /* If nFlush==0, then do not flush any data from the in-memory tree to 
  ** disk. If nFlush==1, then there exists an "old" tree that should be 
  ** flushed to disk if auto-work is enabled. Or if nFlush==2, then both
  ** the old and current trees are large enough to flush to disk. In this
  ** case do so regardless of the auto-work setting.  
  **
  ** If auto-work is enabled and data was written to disk, also sync the 
  ** db and checkpoint the latest snapshot.
  **
  ** Ignore any LSM_BUSY errors that occur during these operations. If
  ** LSM_BUSY does occur, it means some other connection is already working
  ** on flushing the in-memory tree or checkpointing the database. 
  */
  assert( rc!=LSM_BUSY);
  if( rc==LSM_OK && (nFlush>1 || (nFlush && pDb->bAutowork)) ){
    rc = lsmFlushToDisk(pDb);
    if( rc==LSM_OK && pDb->bAutowork ){
      rc = lsmCheckpointWrite(pDb);
    }
  }
  if( rc==LSM_BUSY ) rc = LSM_OK;

  return rc;
}

int lsm_rollback(lsm_db *pDb, int iLevel){
  int rc = LSM_OK;
  assert_db_state( pDb );

    if( rc==LSM_OK ){
      /* Flush the in-memory tree, if required. If there is data to flush,
      ** this will create a new client snapshot in Database.pClient. The
      ** checkpoint (serialization) of this snapshot may be written to disk
      ** by the following block.  */
      rc = lsmTreeLoadHeader(pDb, 0);
      if( rc==LSM_OK && lsmTreeSize(pDb)>0 ){


        rc = lsmFlushToDisk(pDb);
      }

      /* Write a checkpoint to disk. */
      if( rc==LSM_OK ){
        rc = lsmCheckpointWrite(pDb);
      }

................................................................................
    rc = lsmLogBegin(pDb);
  }

  /* If everything was successful, set the "transaction-in-progress" flag
  ** and return LSM_OK. Otherwise, if some error occurred, relinquish the 
  ** WRITER lock and return an error code.  */
  if( rc==LSM_OK ){

    pShm->bWriter = 1;
    pDb->treehdr.iTransId++;



  }else{
    lsmShmLock(pDb, LSM_LOCK_WRITER, LSM_LOCK_UNLOCK, 0);
    if( pDb->pCsr==0 ) lsmFinishReadTrans(pDb);
  }
  return rc;
}

    if( rc==LSM_OK ){
      /* Flush the in-memory tree, if required. If there is data to flush,
      ** this will create a new client snapshot in Database.pClient. The
      ** checkpoint (serialization) of this snapshot may be written to disk
      ** by the following block.  */
      rc = lsmTreeLoadHeader(pDb, 0);
      if( rc==LSM_OK && lsmTreeSize(pDb)>0 ){
        int nFlush = 0;
        lsmTreeMakeOld(pDb, &nFlush);
        if( nFlush ) rc = lsmFlushToDisk(pDb);
      }

      /* Write a checkpoint to disk. */
      if( rc==LSM_OK ){
        rc = lsmCheckpointWrite(pDb);
      }

................................................................................
    rc = lsmLogBegin(pDb);
  }

  /* If everything was successful, set the "transaction-in-progress" flag
  ** and return LSM_OK. Otherwise, if some error occurred, relinquish the 
  ** WRITER lock and return an error code.  */
  if( rc==LSM_OK ){
    TreeHeader *p = &pDb->treehdr;
    pShm->bWriter = 1;
    p->root.iTransId++;
    if( lsmTreeHasOld(pDb) && p->iOldLog==pDb->pClient->iLogOff ){
      lsmTreeDiscardOld(pDb);
    }
  }else{
    lsmShmLock(pDb, LSM_LOCK_WRITER, LSM_LOCK_UNLOCK, 0);
    if( pDb->pCsr==0 ) lsmFinishReadTrans(pDb);
  }
  return rc;
}

  int flags;                      /* Mask of CURSOR_XXX flags */
  int (*xCmp)(void *, int, void *, int);         /* Compare function */
  int eType;                      /* Cache of current key type */
  Blob key;                       /* Cache of current key (or NULL) */
  Blob val;                       /* Cache of current value */

  TreeCursor *pTreeCsr;           /* Single tree cursor */
  int nSegCsr;                    /* Size of aSegCsr[] array */
  LevelCursor *aSegCsr;           /* Array of cursors open on sorted files */
  int nTree;
  int *aTree;
  BtreeCursor *pBtCsr;

  Snapshot *pSnap;

  /* Used by cursors flushing the in-memory tree only */
  int *pnOvfl;                    /* Number of free-list entries to store */
  void *pSystemVal;               /* Pointer to buffer to free */
};

#define CURSOR_DATA_TREE      0

#define CURSOR_DATA_SYSTEM    1
#define CURSOR_DATA_SEGMENT   2


/*
** CURSOR_IGNORE_DELETE
**   If set, this cursor will not visit SORTED_DELETE keys.
**
** CURSOR_NEW_SYSTEM
................................................................................

    lsmFsPageRef(pTest);
    while( pTest ){
      Page *pNext;

      int rc = lsmFsDbPageNext(pPtr->pSeg, pTest, eDir, &pNext);
      lsmFsPageRelease(pTest);

      pTest = pNext;

      if( pTest ){
        int nData;
        u8 *aData = fsPageData(pTest, &nData);
        int nCell = pageGetNRec(aData, nData);
        int flags = pageGetFlags(aData, nData);
................................................................................
}

static void mcursorFreeComponents(MultiCursor *pCsr){
  int i;
  lsm_env *pEnv = pCsr->pDb->pEnv;

  /* Close the tree cursor, if any. */
  lsmTreeCursorDestroy(pCsr->pTreeCsr);


  /* Close the sorted file cursors */
  for(i=0; i<pCsr->nSegCsr; i++){
    segmentCursorClose(pEnv, &pCsr->aSegCsr[i]);
  }

  /* And the b-tree cursor, if any */
................................................................................
  /* Zero fields */
  pCsr->nSegCsr = 0;
  pCsr->aSegCsr = 0;
  pCsr->nTree = 0;
  pCsr->aTree = 0;
  pCsr->pSystemVal = 0;
  pCsr->pSnap = 0;
  pCsr->pTreeCsr = 0;

  pCsr->pBtCsr = 0;
}

void lsmMCursorClose(MultiCursor *pCsr){
  if( pCsr ){
    lsm_db *pDb = pCsr->pDb;
    MultiCursor **pp;             /* Iterator variable */
................................................................................
    }
  }

  return rc;
}








static int multiCursorNew(
  lsm_db *pDb,                    /* Database handle */
  Snapshot *pSnap,                /* Snapshot to use for this cursor */
  int useTree,                    /* If true, search the in-memory tree */
  int bUserOnly,                  /* If true, ignore all system data */
  MultiCursor **ppCsr             /* OUT: Allocated cursor */
){
  int rc = LSM_OK;                /* Return Code */
  MultiCursor *pCsr = *ppCsr;     /* Allocated multi-cursor */



  if( pCsr==0 ){
    pCsr = (MultiCursor *)lsmMallocZeroRc(pDb->pEnv, sizeof(MultiCursor), &rc);
    if( pCsr ){
      pCsr->pNext = pDb->pCsr;
      pDb->pCsr = pCsr;
    }
  }

  if( rc==LSM_OK ){
    if( useTree ){





      rc = lsmTreeCursorNew(pDb, &pCsr->pTreeCsr);

    }
    pCsr->pDb = pDb;
    pCsr->pSnap = pSnap;
    pCsr->xCmp = pDb->xCmp;
    if( bUserOnly ){
      pCsr->flags |= CURSOR_IGNORE_SYSTEM;
    }
................................................................................
  int *pnKey                      /* OUT: Size of *ppKey in bytes */
){
  int nKey = 0;
  void *pKey = 0;
  int eType = 0;

  switch( iKey ){
    case CURSOR_DATA_TREE:


      if( lsmTreeCursorValid(pCsr->pTreeCsr) ){
        int nVal;
        void *pVal;

        lsmTreeCursorKey(pCsr->pTreeCsr, &pKey, &nKey);
        lsmTreeCursorValue(pCsr->pTreeCsr, &pVal, &nVal);
        eType = (nVal<0) ? SORTED_DELETE : SORTED_WRITE;
      }
      break;


    case CURSOR_DATA_SYSTEM:
      if( pCsr->flags & CURSOR_AT_FREELIST ){
        pKey = (void *)"FREELIST";
        nKey = 8;
        eType = SORTED_SYSTEM_WRITE;
      }
................................................................................
static int multiCursorGetVal(
  MultiCursor *pCsr, 
  int iVal, 
  void **ppVal, 
  int *pnVal
){
  int rc = LSM_OK;
  if( iVal==CURSOR_DATA_TREE ){

    if( lsmTreeCursorValid(pCsr->pTreeCsr) ){
      lsmTreeCursorValue(pCsr->pTreeCsr, ppVal, pnVal);
    }else{
      *ppVal = 0;
      *pnVal = 0;
    }
  }else if( iVal==CURSOR_DATA_SYSTEM ){
    if( pCsr->flags & CURSOR_AT_FREELIST ){
      void *aVal;
................................................................................
}

static int multiCursorEnd(MultiCursor *pCsr, int bLast){
  int rc = LSM_OK;
  int i;

  pCsr->flags &= ~(CURSOR_NEXT_OK | CURSOR_PREV_OK);
  if( pCsr->pTreeCsr ){
    rc = lsmTreeCursorEnd(pCsr->pTreeCsr, bLast);
  }





  if( pCsr->flags & CURSOR_NEW_SYSTEM ){
    assert( bLast==0 );
    pCsr->flags |= CURSOR_AT_FREELIST;
  }
  for(i=0; rc==LSM_OK && i<pCsr->nSegCsr; i++){
    rc = segmentCursorEnd(&pCsr->aSegCsr[i], bLast);
  }
................................................................................
  return rc;
}


int mcursorSave(MultiCursor *pCsr){
  int rc = LSM_OK;
  if( pCsr->aTree ){
    if( pCsr->aTree[1]==CURSOR_DATA_TREE ){

      multiCursorCacheKey(pCsr, &rc);
    }
    mcursorFreeComponents(pCsr);
  }
  return rc;
}

................................................................................
  return pCsr->pDb;
}



void lsmMCursorReset(MultiCursor *pCsr){
  int i;
  lsmTreeCursorReset(pCsr->pTreeCsr);

  for(i=0; i<pCsr->nSegCsr; i++){
    segmentCursorReset(&pCsr->aSegCsr[i]);
  }
  pCsr->key.nData = 0;
}






























/*
** Seek the cursor.
*/
int lsmMCursorSeek(MultiCursor *pCsr, void *pKey, int nKey, int eSeek){
  int eESeek = eSeek;             /* Effective eSeek parameter */
  int rc = LSM_OK;
  int i;
  int res; 
  int iPtr = 0; 

  if( eESeek==LSM_SEEK_LEFAST ) eESeek = LSM_SEEK_LE;
  assert( eESeek==LSM_SEEK_EQ || eESeek==LSM_SEEK_LE || eESeek==LSM_SEEK_GE );

  assert( (pCsr->flags & CURSOR_NEW_SYSTEM)==0 );
  assert( (pCsr->flags & CURSOR_AT_FREELIST)==0 );

  pCsr->flags &= ~(CURSOR_NEXT_OK | CURSOR_PREV_OK);
  lsmTreeCursorSeek(pCsr->pTreeCsr, pKey, nKey, &res);
  switch( eESeek ){
    case LSM_SEEK_EQ:
      if( res!=0 ){
        lsmTreeCursorReset(pCsr->pTreeCsr);
      }
      break;
    case LSM_SEEK_GE:
      if( res<0 && lsmTreeCursorValid(pCsr->pTreeCsr) ){
        lsmTreeCursorNext(pCsr->pTreeCsr);
      }
      break;
    default:
      if( res>0 ){
        assert( lsmTreeCursorValid(pCsr->pTreeCsr) );
        lsmTreeCursorPrev(pCsr->pTreeCsr);
      }
      break;
  }

  for(i=0; rc==LSM_OK && i<pCsr->nSegCsr; i++){
    rc = segmentCursorSeek(&pCsr->aSegCsr[i], pKey, nKey, iPtr, eESeek, &iPtr);
  }

  if( rc==LSM_OK ){
    rc = multiCursorAllocTree(pCsr);
................................................................................
  return rc;
}

int lsmMCursorValid(MultiCursor *pCsr){
  int res = 0;
  if( pCsr->aTree ){
    int iKey = pCsr->aTree[1];
    if( iKey==CURSOR_DATA_TREE ){
      res = lsmTreeCursorValid(pCsr->pTreeCsr);
    }else{
      void *pKey; 
      multiCursorGetKey(pCsr, iKey, 0, &pKey, 0);
      res = pKey!=0;
    }
  }
  return res;
................................................................................
}

static int multiCursorAdvance(MultiCursor *pCsr, int bReverse){
  int rc = LSM_OK;                /* Return Code */
  if( lsmMCursorValid(pCsr) ){
    do {
      int iKey = pCsr->aTree[1];
      if( iKey==CURSOR_DATA_TREE ){

        if( bReverse ){
          rc = lsmTreeCursorPrev(pCsr->pTreeCsr);
        }else{
          rc = lsmTreeCursorNext(pCsr->pTreeCsr);
        }
      }else if( iKey==CURSOR_DATA_SYSTEM ){
        assert( pCsr->flags & CURSOR_AT_FREELIST );
        assert( pCsr->flags & CURSOR_NEW_SYSTEM );
        assert( bReverse==0 );
        pCsr->flags &= ~CURSOR_AT_FREELIST;
      }else if( iKey==(CURSOR_DATA_SEGMENT+pCsr->nSegCsr) ){
................................................................................

int lsmMCursorPrev(MultiCursor *pCsr){
  if( (pCsr->flags & CURSOR_PREV_OK)==0 ) return LSM_MISUSE_BKPT;
  return multiCursorAdvance(pCsr, 1);
}

int lsmMCursorKey(MultiCursor *pCsr, void **ppKey, int *pnKey){


  if( pCsr->aTree[1]==CURSOR_DATA_TREE ){

    lsmTreeCursorKey(pCsr->pTreeCsr, ppKey, pnKey);
  }else{
    int nKey;

#ifndef NDEBUG
    void *pKey;
    int eType;
    multiCursorGetKey(pCsr, pCsr->aTree[1], &eType, &pKey, &nKey);
    assert( eType==pCsr->eType );
    assert( nKey==pCsr->key.nData );
    assert( memcmp(pKey, pCsr->key.pData, nKey)==0 );
#endif

    nKey = pCsr->key.nData;
    if( nKey==0 ){
................................................................................
  pNext = lsmDbSnapshotLevel(pDb->pWorker);
  pNew = (Level *)lsmMallocZeroRc(pDb->pEnv, sizeof(Level), &rc);

  /* Create a cursor to gather the data required by the new segment. The new
  ** segment contains everything in the tree and pointers to the next segment
  ** in the database (if any).  */
  if( rc==LSM_OK ){
    rc = multiCursorNew(pDb, pDb->pWorker, bTree, 0, &pCsr);
    if( rc==LSM_OK ){
      pNew->pNext = pNext;
      lsmDbSnapshotSetLevel(pDb->pWorker, pNew);
    }
    if( rc==LSM_OK ){
      if( pNext ){
        assert( pNext->pMerge==0 || pNext->nRight>0 );
................................................................................
  int *pnOvfl                     /* OUT: Number of free-list entries written */
){
  int rc;

  assert( pDb->pWorker );

  /* If there is nothing to do, return early. */
  if( lsmTreeSize(pDb)==0 && lsmCheckpointOverflowRequired(pDb)==0 ){
    *pnOvfl = 0;
    return LSM_OK;
  }

  rc = sortedNewToplevel(pDb, 1, pnOvfl);
  assert( rc!=LSM_OK || lsmFsIntegrityCheck(pDb) );

................................................................................
}

/*
** Perform work to merge database segments together.
*/
int lsm_work(lsm_db *pDb, int flags, int nPage, int *pnWrite){
  int rc = LSM_OK;                /* Return code */





  /* This function may not be called if pDb has an open read or write
  ** transaction. Return LSM_MISUSE if an application attempts this.  */
  if( pDb->nTransOpen || pDb->pCsr ) return LSM_MISUSE_BKPT;

  /* If the FLUSH flag is set, try to flush the contents of the in-memory
  ** tree to disk.  */
  if( (flags & LSM_WORK_FLUSH) ){
    rc = lsmBeginWriteTrans(pDb);
    if( rc==LSM_OK ){
      rc = lsmFlushToDisk(pDb);


      lsmFinishWriteTrans(pDb, 1);
      lsmFinishReadTrans(pDb);
    }

  }

  if( rc==LSM_OK && nPage>0 ){
    int bOptimize = ((flags & LSM_WORK_OPTIMIZE) ? 1 : 0);
    int nWrite = 0;
    int nOvfl = -1;

    assert( pDb->pWorker==0 );

    rc = lsmBeginWork(pDb);







    if( rc==LSM_OK ){
      rc = sortedWork(pDb, nPage, bOptimize, &nWrite);


    }






    if( rc==LSM_OK && nWrite ){
      rc = lsmSortedFlushDb(pDb);
      if( rc==LSM_OK && lsmCheckpointOverflowRequired(pDb) ){

        rc = sortedNewToplevel(pDb, 0, &nOvfl);
      }
    }




    if( nWrite ){
      lsmFinishWork(pDb, 0, nOvfl, &rc);
    }else{
      int rcdummy = LSM_BUSY;
      lsmFinishWork(pDb, 0, 0, &rcdummy);
    }

    assert( pDb->pWorker==0 );
    if( pnWrite ) *pnWrite = nWrite;
  }else if( pnWrite ){
    *pnWrite = 0;
  }

  /* If the LSM_WORK_CHECKPOINT flag is specified and one is available,
  ** write a checkpoint out to disk.  */
  if( rc==LSM_OK && (flags & LSM_WORK_CHECKPOINT) ){
    rc = lsmCheckpointWrite(pDb);
  }

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

  return LSM_OK;
}

void lsmSortedSaveTreeCursors(lsm_db *pDb){
  MultiCursor *pCsr;
  for(pCsr=pDb->pCsr; pCsr; pCsr=pCsr->pNext){
    lsmTreeCursorSave(pCsr->pTreeCsr);

  }
}

#ifdef LSM_DEBUG_EXPENSIVE
/*
** This function is only included in the build if LSM_DEBUG_EXPENSIVE is 
** defined. Its only purpose is to evaluate various assert() statements to 

  int flags;                      /* Mask of CURSOR_XXX flags */
  int (*xCmp)(void *, int, void *, int);         /* Compare function */
  int eType;                      /* Cache of current key type */
  Blob key;                       /* Cache of current key (or NULL) */
  Blob val;                       /* Cache of current value */

  TreeCursor *apTreeCsr[2];       /* One or two tree cursors */
  int nSegCsr;                    /* Size of aSegCsr[] array */
  LevelCursor *aSegCsr;           /* Array of cursors open on sorted files */
  int nTree;
  int *aTree;
  BtreeCursor *pBtCsr;

  Snapshot *pSnap;

  /* Used by cursors flushing the in-memory tree only */
  int *pnOvfl;                    /* Number of free-list entries to store */
  void *pSystemVal;               /* Pointer to buffer to free */
};

#define CURSOR_DATA_TREE0     0   /* Current tree cursor */
#define CURSOR_DATA_TREE1     1   /* The "old" tree, if any */
#define CURSOR_DATA_SYSTEM    2
#define CURSOR_DATA_SEGMENT   3


/*
** CURSOR_IGNORE_DELETE
**   If set, this cursor will not visit SORTED_DELETE keys.
**
** CURSOR_NEW_SYSTEM
................................................................................

    lsmFsPageRef(pTest);
    while( pTest ){
      Page *pNext;

      int rc = lsmFsDbPageNext(pPtr->pSeg, pTest, eDir, &pNext);
      lsmFsPageRelease(pTest);
      if( rc ) return 1;
      pTest = pNext;

      if( pTest ){
        int nData;
        u8 *aData = fsPageData(pTest, &nData);
        int nCell = pageGetNRec(aData, nData);
        int flags = pageGetFlags(aData, nData);
................................................................................
}

static void mcursorFreeComponents(MultiCursor *pCsr){
  int i;
  lsm_env *pEnv = pCsr->pDb->pEnv;

  /* Close the tree cursor, if any. */
  lsmTreeCursorDestroy(pCsr->apTreeCsr[0]);
  lsmTreeCursorDestroy(pCsr->apTreeCsr[1]);

  /* Close the sorted file cursors */
  for(i=0; i<pCsr->nSegCsr; i++){
    segmentCursorClose(pEnv, &pCsr->aSegCsr[i]);
  }

  /* And the b-tree cursor, if any */
................................................................................
  /* Zero fields */
  pCsr->nSegCsr = 0;
  pCsr->aSegCsr = 0;
  pCsr->nTree = 0;
  pCsr->aTree = 0;
  pCsr->pSystemVal = 0;
  pCsr->pSnap = 0;
  pCsr->apTreeCsr[0] = 0;
  pCsr->apTreeCsr[1] = 0;
  pCsr->pBtCsr = 0;
}

void lsmMCursorClose(MultiCursor *pCsr){
  if( pCsr ){
    lsm_db *pDb = pCsr->pDb;
    MultiCursor **pp;             /* Iterator variable */
................................................................................
    }
  }

  return rc;
}


/*
** Parameter iUseTree must be set to 0, 1 or 2. If it is not zero, then a 
** tree cursor is added to the multi-cursor before it is returned. If 
** iUseTree is 1, then the cursor accesses the entire tree. Otherwise, if
** iUseTree is 2, it iterates through the "old" tree only.
*/
static int multiCursorNew(
  lsm_db *pDb,                    /* Database handle */
  Snapshot *pSnap,                /* Snapshot to use for this cursor */
  int iUseTree,                   /* If true, search the in-memory tree */
  int bUserOnly,                  /* If true, ignore all system data */
  MultiCursor **ppCsr             /* OUT: Allocated cursor */
){
  int rc = LSM_OK;                /* Return Code */
  MultiCursor *pCsr = *ppCsr;     /* Allocated multi-cursor */

  assert( iUseTree==0 || iUseTree==1 || iUseTree==2 );

  if( pCsr==0 ){
    pCsr = (MultiCursor *)lsmMallocZeroRc(pDb->pEnv, sizeof(MultiCursor), &rc);
    if( pCsr ){
      pCsr->pNext = pDb->pCsr;
      pDb->pCsr = pCsr;
    }
  }

  if( rc==LSM_OK ){
    if( iUseTree ){
      rc = lsmTreeCursorNew(pDb, iUseTree-1, &pCsr->apTreeCsr[0]);
      if( rc==LSM_OK && lsmTreeHasOld(pDb) 
       && iUseTree==1
       && pDb->treehdr.iOldLog!=pSnap->iLogOff
      ){
        rc = lsmTreeCursorNew(pDb, 1, &pCsr->apTreeCsr[1]);
      }
    }
    pCsr->pDb = pDb;
    pCsr->pSnap = pSnap;
    pCsr->xCmp = pDb->xCmp;
    if( bUserOnly ){
      pCsr->flags |= CURSOR_IGNORE_SYSTEM;
    }
................................................................................
  int *pnKey                      /* OUT: Size of *ppKey in bytes */
){
  int nKey = 0;
  void *pKey = 0;
  int eType = 0;

  switch( iKey ){
    case CURSOR_DATA_TREE0:
    case CURSOR_DATA_TREE1: {
      TreeCursor *pTreeCsr = pCsr->apTreeCsr[iKey-CURSOR_DATA_TREE0];
      if( lsmTreeCursorValid(pTreeCsr) ){
        int nVal;
        void *pVal;

        lsmTreeCursorKey(pTreeCsr, &pKey, &nKey);
        lsmTreeCursorValue(pTreeCsr, &pVal, &nVal);
        eType = (nVal<0) ? SORTED_DELETE : SORTED_WRITE;
      }
      break;
    }

    case CURSOR_DATA_SYSTEM:
      if( pCsr->flags & CURSOR_AT_FREELIST ){
        pKey = (void *)"FREELIST";
        nKey = 8;
        eType = SORTED_SYSTEM_WRITE;
      }
................................................................................
static int multiCursorGetVal(
  MultiCursor *pCsr, 
  int iVal, 
  void **ppVal, 
  int *pnVal
){
  int rc = LSM_OK;
  if( iVal==CURSOR_DATA_TREE0 || iVal==CURSOR_DATA_TREE1 ){
    TreeCursor *pTreeCsr = pCsr->apTreeCsr[iVal-CURSOR_DATA_TREE0];
    if( lsmTreeCursorValid(pTreeCsr) ){
      lsmTreeCursorValue(pTreeCsr, ppVal, pnVal);
    }else{
      *ppVal = 0;
      *pnVal = 0;
    }
  }else if( iVal==CURSOR_DATA_SYSTEM ){
    if( pCsr->flags & CURSOR_AT_FREELIST ){
      void *aVal;
................................................................................
}

static int multiCursorEnd(MultiCursor *pCsr, int bLast){
  int rc = LSM_OK;
  int i;

  pCsr->flags &= ~(CURSOR_NEXT_OK | CURSOR_PREV_OK);
  if( pCsr->apTreeCsr[0] ){
    rc = lsmTreeCursorEnd(pCsr->apTreeCsr[0], bLast);
  }
  if( rc==LSM_OK && pCsr->apTreeCsr[1] ){
    rc = lsmTreeCursorEnd(pCsr->apTreeCsr[1], bLast);
  }


  if( pCsr->flags & CURSOR_NEW_SYSTEM ){
    assert( bLast==0 );
    pCsr->flags |= CURSOR_AT_FREELIST;
  }
  for(i=0; rc==LSM_OK && i<pCsr->nSegCsr; i++){
    rc = segmentCursorEnd(&pCsr->aSegCsr[i], bLast);
  }
................................................................................
  return rc;
}


int mcursorSave(MultiCursor *pCsr){
  int rc = LSM_OK;
  if( pCsr->aTree ){
    int iTree = pCsr->aTree[1];
    if( iTree==CURSOR_DATA_TREE0 || iTree==CURSOR_DATA_TREE1 ){
      multiCursorCacheKey(pCsr, &rc);
    }
    mcursorFreeComponents(pCsr);
  }
  return rc;
}

................................................................................
  return pCsr->pDb;
}



void lsmMCursorReset(MultiCursor *pCsr){
  int i;
  lsmTreeCursorReset(pCsr->apTreeCsr[0]);
  lsmTreeCursorReset(pCsr->apTreeCsr[1]);
  for(i=0; i<pCsr->nSegCsr; i++){
    segmentCursorReset(&pCsr->aSegCsr[i]);
  }
  pCsr->key.nData = 0;
}

static void treeCursorSeek(
  TreeCursor *pTreeCsr, 
  void *pKey, int nKey, 
  int eSeek
){
  if( pTreeCsr ){
    int res = 0;
    lsmTreeCursorSeek(pTreeCsr, pKey, nKey, &res);
    switch( eSeek ){
      case LSM_SEEK_EQ:
        if( res!=0 ){
          lsmTreeCursorReset(pTreeCsr);
        }
        break;
      case LSM_SEEK_GE:
        if( res<0 && lsmTreeCursorValid(pTreeCsr) ){
          lsmTreeCursorNext(pTreeCsr);
        }
        break;
      default:
        if( res>0 ){
          assert( lsmTreeCursorValid(pTreeCsr) );
          lsmTreeCursorPrev(pTreeCsr);
        }
        break;
    }
  }
}

/*
** Seek the cursor.
*/
int lsmMCursorSeek(MultiCursor *pCsr, void *pKey, int nKey, int eSeek){
  int eESeek = eSeek;             /* Effective eSeek parameter */
  int rc = LSM_OK;
  int i;

  int iPtr = 0; 

  if( eESeek==LSM_SEEK_LEFAST ) eESeek = LSM_SEEK_LE;
  assert( eESeek==LSM_SEEK_EQ || eESeek==LSM_SEEK_LE || eESeek==LSM_SEEK_GE );

  assert( (pCsr->flags & CURSOR_NEW_SYSTEM)==0 );
  assert( (pCsr->flags & CURSOR_AT_FREELIST)==0 );

  pCsr->flags &= ~(CURSOR_NEXT_OK | CURSOR_PREV_OK);
  treeCursorSeek(pCsr->apTreeCsr[0], pKey, nKey, eESeek);
  treeCursorSeek(pCsr->apTreeCsr[1], pKey, nKey, eESeek);


















  for(i=0; rc==LSM_OK && i<pCsr->nSegCsr; i++){
    rc = segmentCursorSeek(&pCsr->aSegCsr[i], pKey, nKey, iPtr, eESeek, &iPtr);
  }

  if( rc==LSM_OK ){
    rc = multiCursorAllocTree(pCsr);
................................................................................
  return rc;
}

int lsmMCursorValid(MultiCursor *pCsr){
  int res = 0;
  if( pCsr->aTree ){
    int iKey = pCsr->aTree[1];
    if( iKey==CURSOR_DATA_TREE0 || iKey==CURSOR_DATA_TREE1 ){
      res = lsmTreeCursorValid(pCsr->apTreeCsr[iKey-CURSOR_DATA_TREE0]);
    }else{
      void *pKey; 
      multiCursorGetKey(pCsr, iKey, 0, &pKey, 0);
      res = pKey!=0;
    }
  }
  return res;
................................................................................
}

static int multiCursorAdvance(MultiCursor *pCsr, int bReverse){
  int rc = LSM_OK;                /* Return Code */
  if( lsmMCursorValid(pCsr) ){
    do {
      int iKey = pCsr->aTree[1];
      if( iKey==CURSOR_DATA_TREE0 || iKey==CURSOR_DATA_TREE1 ){
        TreeCursor *pTreeCsr = pCsr->apTreeCsr[iKey-CURSOR_DATA_TREE0];
        if( bReverse ){
          rc = lsmTreeCursorPrev(pTreeCsr);
        }else{
          rc = lsmTreeCursorNext(pTreeCsr);
        }
      }else if( iKey==CURSOR_DATA_SYSTEM ){
        assert( pCsr->flags & CURSOR_AT_FREELIST );
        assert( pCsr->flags & CURSOR_NEW_SYSTEM );
        assert( bReverse==0 );
        pCsr->flags &= ~CURSOR_AT_FREELIST;
      }else if( iKey==(CURSOR_DATA_SEGMENT+pCsr->nSegCsr) ){
................................................................................

int lsmMCursorPrev(MultiCursor *pCsr){
  if( (pCsr->flags & CURSOR_PREV_OK)==0 ) return LSM_MISUSE_BKPT;
  return multiCursorAdvance(pCsr, 1);
}

int lsmMCursorKey(MultiCursor *pCsr, void **ppKey, int *pnKey){
  int iKey = pCsr->aTree[1];

  if( iKey==CURSOR_DATA_TREE0 || iKey==CURSOR_DATA_TREE1 ){
    TreeCursor *pTreeCsr = pCsr->apTreeCsr[iKey-CURSOR_DATA_TREE0];
    lsmTreeCursorKey(pTreeCsr, ppKey, pnKey);
  }else{
    int nKey;

#ifndef NDEBUG
    void *pKey;
    int eType;
    multiCursorGetKey(pCsr, iKey, &eType, &pKey, &nKey);
    assert( eType==pCsr->eType );
    assert( nKey==pCsr->key.nData );
    assert( memcmp(pKey, pCsr->key.pData, nKey)==0 );
#endif

    nKey = pCsr->key.nData;
    if( nKey==0 ){
................................................................................
  pNext = lsmDbSnapshotLevel(pDb->pWorker);
  pNew = (Level *)lsmMallocZeroRc(pDb->pEnv, sizeof(Level), &rc);

  /* Create a cursor to gather the data required by the new segment. The new
  ** segment contains everything in the tree and pointers to the next segment
  ** in the database (if any).  */
  if( rc==LSM_OK ){
    rc = multiCursorNew(pDb, pDb->pWorker, (bTree ? 2 : 0), 0, &pCsr);
    if( rc==LSM_OK ){
      pNew->pNext = pNext;
      lsmDbSnapshotSetLevel(pDb->pWorker, pNew);
    }
    if( rc==LSM_OK ){
      if( pNext ){
        assert( pNext->pMerge==0 || pNext->nRight>0 );
................................................................................
  int *pnOvfl                     /* OUT: Number of free-list entries written */
){
  int rc;

  assert( pDb->pWorker );

  /* If there is nothing to do, return early. */
  if( lsmTreeHasOld(pDb)==0 && lsmCheckpointOverflowRequired(pDb)==0 ){
    *pnOvfl = 0;
    return LSM_OK;
  }

  rc = sortedNewToplevel(pDb, 1, pnOvfl);
  assert( rc!=LSM_OK || lsmFsIntegrityCheck(pDb) );

................................................................................
}

/*
** Perform work to merge database segments together.
*/
int lsm_work(lsm_db *pDb, int flags, int nPage, int *pnWrite){
  int rc = LSM_OK;                /* Return code */
  int nOvfl = 0;
  int bFlush = 0;
  int bFinishWork = 0;
  int nWrite = 0;

  /* This function may not be called if pDb has an open read or write
  ** transaction. Return LSM_MISUSE if an application attempts this.  */
  if( pDb->nTransOpen || pDb->pCsr ) return LSM_MISUSE_BKPT;



  if( (flags & LSM_WORK_FLUSH) && (flags & LSM_WORK_OPTIMIZE) ){
    rc = lsmBeginWriteTrans(pDb);
    if( rc==LSM_OK ){

      int nDummy;
      lsmTreeMakeOld(pDb, &nDummy);
      lsmFinishWriteTrans(pDb, 1);
      lsmFinishReadTrans(pDb);
    }
    if( rc==LSM_BUSY ) rc = LSM_OK;
  }






  assert( pDb->pWorker==0 );
  if( (flags & LSM_WORK_FLUSH) || nPage>0 ){
    rc = lsmBeginWork(pDb);
    bFinishWork = 1;
  }

  /* If the FLUSH flag is set, try to flush the contents of the in-memory
  ** tree to disk.  */
  if( rc==LSM_OK && ((flags & LSM_WORK_FLUSH)) ){
    rc = lsmTreeLoadHeader(pDb, 0);
    if( rc==LSM_OK && pDb->treehdr.iOldShmid ){

      rc = lsmSortedFlushTree(pDb, &nOvfl);
      bFlush = 1;
    }
  }

  /* If nPage is greater than zero, do some merging. */
  if( rc==LSM_OK && nPage>0 ){
    int bOptimize = ((flags & LSM_WORK_OPTIMIZE) ? 1 : 0);
    rc = sortedWork(pDb, nPage, bOptimize, &nWrite);
    if( rc==LSM_OK && nWrite ){
      rc = lsmSortedFlushDb(pDb);
      if( rc==LSM_OK && lsmCheckpointOverflowRequired(pDb) ){
        nOvfl = -1;
        rc = sortedNewToplevel(pDb, 0, &nOvfl);
      }
    }
  }

  if( pnWrite ) *pnWrite = nWrite;
  if( bFinishWork ){
    if( nWrite || bFlush ){
      lsmFinishWork(pDb, bFlush, nOvfl, &rc);
    }else{
      int rcdummy = LSM_BUSY;
      lsmFinishWork(pDb, 0, 0, &rcdummy);
    }
  }
  assert( pDb->pWorker==0 );





  /* If the LSM_WORK_CHECKPOINT flag is specified and one is available,
  ** write a checkpoint out to disk.  */
  if( rc==LSM_OK && (flags & LSM_WORK_CHECKPOINT) ){
    rc = lsmCheckpointWrite(pDb);
  }

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

  return LSM_OK;
}

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
/*
** This function is only included in the build if LSM_DEBUG_EXPENSIVE is 
** defined. Its only purpose is to evaluate various assert() statements to 

#define MAX_DEPTH 32

typedef struct TreeKey TreeKey;
typedef struct TreeNode TreeNode;
typedef struct TreeLeaf TreeLeaf;
typedef struct NodeVersion NodeVersion;







/*
** Container for a key-value pair. Within the *-shm file, each key/value
** pair is stored in a single allocation (which may not actually be 
** contiguous in memory). Layout is the TreeKey structure, followed by
** the nKey bytes of key blob, followed by the nValue bytes of value blob
** (if nValue is non-negative).
*/
................................................................................
** Entries in the apTreeNode[] and aiCell[] arrays contain the node and
** index of the TreeNode.apChild[] pointer followed to descend to the 
** current element. Hence apTreeNode[0] always contains the root node of
** the tree.
*/
struct TreeCursor {
  lsm_db *pDb;                    /* Database handle for this cursor */

  int iNode;                      /* Cursor points at apTreeNode[iNode] */
  TreeNode *apTreeNode[MAX_DEPTH];/* Current position in tree */
  u8 aiCell[MAX_DEPTH];           /* Current position in tree */
  TreeKey *pSave;                 /* Saved key */
  TreeBlob blob;                  /* Dynamic storage for a key */
};

................................................................................
/*
** Run various assert() statements to check that the working-version of the
** tree is correct in the following respects:
**
**   * todo...
*/
void assert_tree_looks_ok(int rc, Tree *pTree){
  if( rc==LSM_OK ){
    TreeVersion *p = pTree->pWorking ? pTree->pWorking : pTree->pCommit;
    if( p ){
      assert( (p->nHeight==0)==(p->pRoot==0) );
      assert_node_looks_ok(p->pRoot, p->nHeight);
    }
  }
}
#else
# define assert_tree_looks_ok(x,y)
#endif

#ifdef LSM_DEBUG

................................................................................
    }
  }

  printf("%s\n", s.z);
  lsmStringClear(&s);

  for(i=0; i<4 && nHeight>0; i++){
    u32 iPtr = getChildPtr(pNode, pDb->treehdr.iTransId, i);
    if( iPtr ){
      dump_node_contents(pDb, iPtr, nIndent + 2, nHeight-1);
    }
  }

  tblobFree(pDb, &b);
}

void dump_tree_contents(lsm_db *pDb, const char *zCaption){

  printf("\n%s\n", zCaption);
  if( pDb->treehdr.iRoot ){

    dump_node_contents(pDb, pDb->treehdr.iRoot, 0, pDb->treehdr.nHeight-1);
  }
  fflush(stdout);
}

#endif

/*
** Initialize a cursor object, the space for which has already been
** allocated.
*/
static void treeCursorInit(lsm_db *pDb, TreeCursor *pCsr){
  memset(pCsr, 0, sizeof(TreeCursor));
  pCsr->pDb = pDb;





  pCsr->iNode = -1;
}

/*
** Return a pointer to the mapping of the TreeKey object that the cursor
** is pointing to. 
*/
................................................................................
}

/*
** Save the current position of tree cursor pCsr.
*/
int lsmTreeCursorSave(TreeCursor *pCsr){
  int rc = LSM_OK;
  if( pCsr->pSave==0 ){
    int iNode = pCsr->iNode;
    if( iNode>=0 ){
      pCsr->pSave = csrGetKey(pCsr, &pCsr->blob, &rc);
    }
    pCsr->iNode = -1;
  }
  return rc;
................................................................................
){
  TreeKey *p;
  u32 iPtr;
  int nRem;
  u8 *a;
  int n;

#if 0
  nRem = sizeof(TreeKey) + nKey + (nVal>0 ? nVal : 0);
  *piPtr = iPtr = treeShmalloc(pDb, 1, nRem, pRc);
  p = treeShmptr(pDb, iPtr, pRc);
  if( *pRc ) return 0;
  p->nKey = nKey;
  p->nValue = nVal;
  memcpy(&p[1], pKey, nKey);
  if( nVal>0 ) memcpy(((u8 *)&p[1]) + nKey, pVal, nVal);
  return p;
#endif

  /* Allocate space for the TreeKey structure itself */
  *piPtr = iPtr = treeShmalloc(pDb, 1, sizeof(TreeKey), pRc);
  p = treeShmptr(pDb, iPtr, pRc);
  if( *pRc ) return 0;
  p->nKey = nKey;
  p->nValue = nVal;

................................................................................
** internal node, or by allocating a new TreeNode structure and then 
** calling this function on the parent of the internal node.
*/
static int treeUpdatePtr(lsm_db *pDb, TreeCursor *pCsr, u32 iNew){
  int rc = LSM_OK;
  if( pCsr->iNode<0 ){
    /* iNew is the new root node */
    pDb->treehdr.iRoot = iNew;
  }else{
    /* If this node already has version 2 content, allocate a copy and
    ** update the copy with the new pointer value. Otherwise, store the
    ** new pointer as v2 data within the current node structure.  */

    TreeNode *p;                  /* The node to be modified */
    int iChildPtr;                /* apChild[] entry to modify */
................................................................................
        pCopy->aiChildPtr[iChildPtr] = iNew;
        pCsr->iNode--;
        rc = treeUpdatePtr(pDb, pCsr, iCopy);
      }
    }else{
      /* The "v2 data" option */
      u32 iPtr;
      assert( pDb->treehdr.iTransId>0 );

      if( pCsr->iNode ){
        iPtr = getChildPtr(
            pCsr->apTreeNode[pCsr->iNode-1], 
            pDb->treehdr.iTransId, pCsr->aiCell[pCsr->iNode-1]
        );
      }else{
        iPtr = pDb->treehdr.iRoot;
      }
      rc = intArrayAppend(pDb->pEnv, &pDb->rollback, iPtr);

      if( rc==LSM_OK ){
        p->iV2 = pDb->treehdr.iTransId;
        p->iV2Child = (u8)iChildPtr;
        p->iV2Ptr = iNew;
      }
    }
  }

  return rc;
................................................................................
      u32 iRoot; TreeNode *pRoot; /* New root node */

      pRoot = newTreeNode(pDb, &iRoot, &rc);
      pRoot->aiKeyPtr[1] = pNode->aiKeyPtr[1];
      pRoot->aiChildPtr[1] = iLeft;
      pRoot->aiChildPtr[2] = iRight;

      pDb->treehdr.iRoot = iRoot;
      pDb->treehdr.nHeight++;
    }else{

      pCsr->iNode--;
      rc = treeInsert(pDb, pCsr, 
          iLeft, pNode->aiKeyPtr[1], iRight, pCsr->aiCell[pCsr->iNode]
      );
    }
................................................................................
  return rc;
}

/*
** Empty the contents of the in-memory tree.
*/
void lsmTreeClear(lsm_db *pDb){
  pDb->treehdr.iTransId = 1;
  pDb->treehdr.iRoot = 0;
  pDb->treehdr.nHeight = 0;
  pDb->treehdr.nByte = 0;
  pDb->treehdr.iUsedShmid = pDb->treehdr.iNextShmid-1;
}































/*
** This function is called during recovery to initialize the 
** tree header. Only the database connections private copy of the tree-header
** is initialized here - it will be copied into shared memory if log file
** recovery is successful.
*/
int lsmTreeInit(lsm_db *pDb){
  ShmChunk *pOne;
  int rc = LSM_OK;

  pDb->treehdr.iTransId = 1;
  pDb->treehdr.iFirst = 1;
  pDb->treehdr.nChunk = 2;
  pDb->treehdr.iWrite = LSM_SHM_CHUNK_SIZE + LSM_SHM_CHUNK_HDR;
  pDb->treehdr.iNextShmid = 2;
  pDb->treehdr.iUsedShmid = 1;

  pOne = treeShmChunkRc(pDb, 1, &rc);
................................................................................
/*
** Iterate through the current in-memory tree. If there are any v2-pointers
** with transaction ids larger than db->treehdr.iTransId, zero them.
*/
static int treeRepairPtrs(lsm_db *db){
  int rc = LSM_OK;

  if( db->treehdr.nHeight>1 ){
    TreeCursor csr;               /* Cursor used to iterate through tree */
    u32 iTransId = db->treehdr.iTransId;

    /* Initialize the cursor structure. Also decrement the nHeight variable
    ** in the tree-header. This will prevent the cursor from visiting any
    ** leaf nodes.  */
    db->treehdr.nHeight--;
    treeCursorInit(db, &csr);

    rc = lsmTreeCursorEnd(&csr, 0);
    while( rc==LSM_OK && lsmTreeCursorValid(&csr) ){
      TreeNode *pNode = csr.apTreeNode[csr.iNode];
      if( pNode->iV2>iTransId ){
        pNode->iV2Child = 0;
        pNode->iV2Ptr = 0;
        pNode->iV2 = 0;
      }
      rc = lsmTreeCursorNext(&csr);
    }
    tblobFree(csr.pDb, &csr.blob);

    db->treehdr.nHeight++;
  }

  return rc;
}

static int treeRepairList(lsm_db *db){
  int rc = LSM_OK;
................................................................................
  int nKey,                       /* Size of key data in bytes */
  void *pVal,                     /* Pointer to value data (or NULL) */
  int nVal                        /* Bytes in value data (or -ve for delete) */
){
  int rc = LSM_OK;                /* Return Code */
  TreeKey *pTreeKey;              /* New key-value being inserted */
  u32 iTreeKey;
  TreeHeader *pHdr = &pDb->treehdr;

  assert( nVal>=0 || pVal==0 );
  assert_tree_looks_ok(LSM_OK, pTree);
#if 0
  dump_tree_contents(pDb, "before");
#endif

  /* Allocate and populate a new key-value pair structure */
  pTreeKey = newTreeKey(pDb, &iTreeKey, pKey, nKey, pVal, nVal, &rc);
  if( rc!=LSM_OK ) return rc;

  if( pHdr->iRoot==0 ){
    /* The tree is completely empty. Add a new root node and install
    ** (pKey/nKey) as the middle entry. Even though it is a leaf at the
    ** moment, use newTreeNode() to allocate the node (i.e. allocate enough
    ** space for the fields used by interior nodes). This is because the
    ** treeInsert() routine may convert this node to an interior node. */
    TreeNode *pRoot = newTreeNode(pDb, &pHdr->iRoot, &rc);
    if( rc==LSM_OK ){
      assert( pHdr->nHeight==0 );
      pRoot->aiKeyPtr[1] = iTreeKey;
      pHdr->nHeight = 1;
    }
  }else{
    TreeCursor csr;
    int res;

    /* Seek to the leaf (or internal node) that the new key belongs on */
    treeCursorInit(pDb, &csr);
    lsmTreeCursorSeek(&csr, pKey, nKey, &res);

    if( res==0 ){
      /* The search found a match within the tree. */
      TreeNode *pNew;
      u32 iNew;
      TreeNode *pNode = csr.apTreeNode[csr.iNode];
      int iCell = csr.aiCell[csr.iNode];

      /* Create a copy of this node */
      if( (csr.iNode>0 && csr.iNode==(pHdr->nHeight-1)) ){
        pNew = copyTreeLeaf(pDb, (TreeLeaf *)pNode, &iNew, &rc);
      }else{
        pNew = copyTreeNode(pDb, pNode, &iNew, &rc);
      }

      if( rc==LSM_OK ){
        /* Modify the value in the new version */
................................................................................
int lsmTreeSize(lsm_db *pDb){
  return pDb->treehdr.nByte;
}

/*
** Open a cursor on the in-memory tree pTree.
*/
int lsmTreeCursorNew(lsm_db *pDb, TreeCursor **ppCsr){
  TreeCursor *pCsr;
  *ppCsr = pCsr = lsmMalloc(pDb->pEnv, sizeof(TreeCursor));
  if( pCsr ){
    treeCursorInit(pDb, pCsr);
    return LSM_OK;
  }
  return LSM_NOMEM_BKPT;
}

/*
** Close an in-memory tree cursor.
................................................................................
  if( pCsr ){
    tblobFree(pCsr->pDb, &pCsr->blob);
    lsmFree(pCsr->pDb->pEnv, pCsr);
  }
}

void lsmTreeCursorReset(TreeCursor *pCsr){

  pCsr->iNode = -1;
  pCsr->pSave = 0;

}

#ifndef NDEBUG
static int treeCsrCompare(TreeCursor *pCsr, void *pKey, int nKey){
  TreeKey *p;
  int cmp = 0;
  int rc = LSM_OK;
................................................................................
**     is smaller than the key and set *pRes to -1, or
**
**   * If the tree is empty, leave the cursor at EOF and set *pRes to -1.
*/
int lsmTreeCursorSeek(TreeCursor *pCsr, void *pKey, int nKey, int *pRes){
  int rc = LSM_OK;                /* Return code */
  lsm_db *pDb = pCsr->pDb;
  TreeHeader *pHdr = &pCsr->pDb->treehdr;
  int (*xCmp)(void *, int, void *, int) = pDb->xCmp;

  u32 iNodePtr;                   /* Location of current node in search */

  /* Discard any saved position data */
  treeCursorRestore(pCsr, 0);

  iNodePtr = pDb->treehdr.iRoot;
  if( iNodePtr==0 ){
    /* Either an error occurred or the tree is completely empty. */
    assert( rc!=LSM_OK || pDb->treehdr.iRoot==0 );
    *pRes = -1;
    pCsr->iNode = -1;
  }else{
    TreeBlob b = {0, 0};
    int res = 0;                  /* Result of comparison function */
    int iNode = -1;
    while( iNodePtr ){
................................................................................
        res = xCmp((void *)&pTreeKey[1], pTreeKey->nKey, pKey, nKey);
        if( res==0 ){
          pCsr->aiCell[iNode] = iTest;
          break;
        }
      }

      if( iNode<(pHdr->nHeight-1) ){
        iNodePtr = getChildPtr(pNode, pDb->treehdr.iTransId, iTest + (res<0));
      }else{
        iNodePtr = 0;
      }
      pCsr->aiCell[iNode] = iTest + (iNodePtr && (res<0));
    }

    *pRes = res;
................................................................................

int lsmTreeCursorNext(TreeCursor *pCsr){
#ifndef NDEBUG
  TreeKey *pK1;
  TreeBlob key1 = {0, 0};
#endif
  lsm_db *pDb = pCsr->pDb;

  const int iLeaf = pDb->treehdr.nHeight-1;
  int iCell; 
  int rc = LSM_OK; 
  TreeNode *pNode; 

  /* Restore the cursor position, if required */
  int iRestore = 0;
  treeCursorRestore(pCsr, &iRestore);
................................................................................

  pNode = pCsr->apTreeNode[pCsr->iNode];
  iCell = ++pCsr->aiCell[pCsr->iNode];

  /* If the current node is not a leaf, and the current cell has sub-tree
  ** associated with it, descend to the left-most key on the left-most
  ** leaf of the sub-tree.  */
  if( pCsr->iNode<iLeaf && getChildPtr(pNode, pDb->treehdr.iTransId, iCell) ){
    do {
      u32 iNodePtr;
      pCsr->iNode++;
      iNodePtr = getChildPtr(pNode, pDb->treehdr.iTransId, iCell);
      pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
      pCsr->apTreeNode[pCsr->iNode] = pNode;
      iCell = pCsr->aiCell[pCsr->iNode] = (pNode->aiKeyPtr[0]==0);
    }while( pCsr->iNode < iLeaf );
  }

  /* Otherwise, the next key is found by following pointer up the tree 
................................................................................

int lsmTreeCursorPrev(TreeCursor *pCsr){
#ifndef NDEBUG
  TreeKey *pK1;
  TreeBlob key1 = {0, 0};
#endif
  lsm_db *pDb = pCsr->pDb;

  const int iLeaf = pDb->treehdr.nHeight-1;
  int iCell; 
  int rc = LSM_OK; 
  TreeNode *pNode; 

  /* Restore the cursor position, if required */
  int iRestore = 0;
  treeCursorRestore(pCsr, &iRestore);
................................................................................
  pNode = pCsr->apTreeNode[pCsr->iNode];
  iCell = pCsr->aiCell[pCsr->iNode];
  assert( iCell>=0 && iCell<3 );

  /* If the current node is not a leaf, and the current cell has sub-tree
  ** associated with it, descend to the right-most key on the right-most
  ** leaf of the sub-tree.  */
  if( pCsr->iNode<iLeaf && getChildPtr(pNode, pDb->treehdr.iTransId, iCell) ){
    do {
      u32 iNodePtr;
      pCsr->iNode++;
      iNodePtr = getChildPtr(pNode, pDb->treehdr.iTransId, iCell);
      pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
      if( rc!=LSM_OK ) break;
      pCsr->apTreeNode[pCsr->iNode] = pNode;
      iCell = 1 + (pNode->aiKeyPtr[2]!=0) + (pCsr->iNode < iLeaf);
      pCsr->aiCell[pCsr->iNode] = iCell;
    }while( pCsr->iNode < iLeaf );
  }
................................................................................
/*
** Move the cursor to the first (bLast==0) or last (bLast!=0) entry in the
** in-memory tree.
*/
int lsmTreeCursorEnd(TreeCursor *pCsr, int bLast){
  lsm_db *pDb = pCsr->pDb;
  TreeHeader *pHdr = &pDb->treehdr;

  int rc = LSM_OK;

  u32 iNodePtr;
  pCsr->iNode = -1;

  /* Discard any saved position data */
  treeCursorRestore(pCsr, 0);

  iNodePtr = pHdr->iRoot;
  while( iNodePtr ){
    int iCell;
    TreeNode *pNode;

    pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
    if( rc ) break;

................................................................................
      iCell = ((pNode->aiKeyPtr[2]==0) ? 2 : 3);
    }else{
      iCell = ((pNode->aiKeyPtr[0]==0) ? 1 : 0);
    }
    pCsr->iNode++;
    pCsr->apTreeNode[pCsr->iNode] = pNode;

    if( pCsr->iNode<pHdr->nHeight-1 ){
      iNodePtr = getChildPtr(pNode, pHdr->iTransId, iCell);
    }else{
      iNodePtr = 0;
    }
    pCsr->aiCell[pCsr->iNode] = iCell - (iNodePtr==0 && bLast);
  }

  return rc;
................................................................................

/*
** Store a mark in *pMark. Later on, a call to lsmTreeRollback() with a
** pointer to the same TreeMark structure may be used to roll the tree
** contents back to their current state.
*/
void lsmTreeMark(lsm_db *pDb, TreeMark *pMark){
  pMark->iRoot = pDb->treehdr.iRoot;
  pMark->nHeight = pDb->treehdr.nHeight;
  pMark->iWrite = pDb->treehdr.iWrite;
  pMark->nChunk = pDb->treehdr.nChunk;
  pMark->iNextShmid = pDb->treehdr.iNextShmid;
  pMark->iRollback = intArraySize(&pDb->rollback);
}

/*
................................................................................
      pFree->iNext = pDb->treehdr.iFirst;
      pFree->iShmid = iShmid--;
      pDb->treehdr.iFirst = iFree;
    }
  }

  /* Restore the tree-header fields */
  pDb->treehdr.iRoot = pMark->iRoot;
  pDb->treehdr.nHeight = pMark->nHeight;
  pDb->treehdr.iWrite = pMark->iWrite;
  pDb->treehdr.nChunk = pMark->nChunk;
  pDb->treehdr.iNextShmid = pMark->iNextShmid;
}

/*
** Load the in-memory tree header from shared-memory into pDb->treehdr.
................................................................................
  }
  pShm->bWriter = 0;
  intArrayFree(pDb->pEnv, &pDb->rollback);

  return LSM_OK;
}

/*
** Begin a new transaction.
*/
int lsmTreeBeginTransaction(lsm_db *pDb){
  pDb->treehdr.iTransId++;
  return LSM_OK;
}

#define MAX_DEPTH 32

typedef struct TreeKey TreeKey;
typedef struct TreeNode TreeNode;
typedef struct TreeLeaf TreeLeaf;
typedef struct NodeVersion NodeVersion;

struct TreeOld {
  u32 iShmid;                     /* Last shared-memory chunk in use by old */
  u32 iRoot;                      /* Offset of root node in shm file */
  u32 nHeight;                    /* Height of tree structure */
};

/*
** Container for a key-value pair. Within the *-shm file, each key/value
** pair is stored in a single allocation (which may not actually be 
** contiguous in memory). Layout is the TreeKey structure, followed by
** the nKey bytes of key blob, followed by the nValue bytes of value blob
** (if nValue is non-negative).
*/
................................................................................
** Entries in the apTreeNode[] and aiCell[] arrays contain the node and
** index of the TreeNode.apChild[] pointer followed to descend to the 
** current element. Hence apTreeNode[0] always contains the root node of
** the tree.
*/
struct TreeCursor {
  lsm_db *pDb;                    /* Database handle for this cursor */
  TreeRoot *pRoot;                /* Root node and height of tree to access */
  int iNode;                      /* Cursor points at apTreeNode[iNode] */
  TreeNode *apTreeNode[MAX_DEPTH];/* Current position in tree */
  u8 aiCell[MAX_DEPTH];           /* Current position in tree */
  TreeKey *pSave;                 /* Saved key */
  TreeBlob blob;                  /* Dynamic storage for a key */
};

................................................................................
/*
** Run various assert() statements to check that the working-version of the
** tree is correct in the following respects:
**
**   * todo...
*/
void assert_tree_looks_ok(int rc, Tree *pTree){







}
#else
# define assert_tree_looks_ok(x,y)
#endif

#ifdef LSM_DEBUG

................................................................................
    }
  }

  printf("%s\n", s.z);
  lsmStringClear(&s);

  for(i=0; i<4 && nHeight>0; i++){
    u32 iPtr = getChildPtr(pNode, pDb->treehdr.root.iTransId, i);
    if( iPtr ){
      dump_node_contents(pDb, iPtr, nIndent + 2, nHeight-1);
    }
  }

  tblobFree(pDb, &b);
}

void dump_tree_contents(lsm_db *pDb, const char *zCaption){
  TreeRoot *p = &pDb->treehdr.root;
  printf("\n%s\n", zCaption);

  if( p->iRoot ){
    dump_node_contents(pDb, p->iRoot, 0, p->nHeight-1);
  }
  fflush(stdout);
}

#endif

/*
** Initialize a cursor object, the space for which has already been
** allocated.
*/
static void treeCursorInit(lsm_db *pDb, int bOld, TreeCursor *pCsr){
  memset(pCsr, 0, sizeof(TreeCursor));
  pCsr->pDb = pDb;
  if( bOld ){
    pCsr->pRoot = &pDb->treehdr.oldroot;
  }else{
    pCsr->pRoot = &pDb->treehdr.root;
  }
  pCsr->iNode = -1;
}

/*
** Return a pointer to the mapping of the TreeKey object that the cursor
** is pointing to. 
*/
................................................................................
}

/*
** Save the current position of tree cursor pCsr.
*/
int lsmTreeCursorSave(TreeCursor *pCsr){
  int rc = LSM_OK;
  if( pCsr && pCsr->pSave==0 ){
    int iNode = pCsr->iNode;
    if( iNode>=0 ){
      pCsr->pSave = csrGetKey(pCsr, &pCsr->blob, &rc);
    }
    pCsr->iNode = -1;
  }
  return rc;
................................................................................
){
  TreeKey *p;
  u32 iPtr;
  int nRem;
  u8 *a;
  int n;













  /* Allocate space for the TreeKey structure itself */
  *piPtr = iPtr = treeShmalloc(pDb, 1, sizeof(TreeKey), pRc);
  p = treeShmptr(pDb, iPtr, pRc);
  if( *pRc ) return 0;
  p->nKey = nKey;
  p->nValue = nVal;

................................................................................
** internal node, or by allocating a new TreeNode structure and then 
** calling this function on the parent of the internal node.
*/
static int treeUpdatePtr(lsm_db *pDb, TreeCursor *pCsr, u32 iNew){
  int rc = LSM_OK;
  if( pCsr->iNode<0 ){
    /* iNew is the new root node */
    pDb->treehdr.root.iRoot = iNew;
  }else{
    /* If this node already has version 2 content, allocate a copy and
    ** update the copy with the new pointer value. Otherwise, store the
    ** new pointer as v2 data within the current node structure.  */

    TreeNode *p;                  /* The node to be modified */
    int iChildPtr;                /* apChild[] entry to modify */
................................................................................
        pCopy->aiChildPtr[iChildPtr] = iNew;
        pCsr->iNode--;
        rc = treeUpdatePtr(pDb, pCsr, iCopy);
      }
    }else{
      /* The "v2 data" option */
      u32 iPtr;
      assert( pDb->treehdr.root.iTransId>0 );

      if( pCsr->iNode ){
        iPtr = getChildPtr(
            pCsr->apTreeNode[pCsr->iNode-1], 
            pDb->treehdr.root.iTransId, pCsr->aiCell[pCsr->iNode-1]
        );
      }else{
        iPtr = pDb->treehdr.root.iRoot;
      }
      rc = intArrayAppend(pDb->pEnv, &pDb->rollback, iPtr);

      if( rc==LSM_OK ){
        p->iV2 = pDb->treehdr.root.iTransId;
        p->iV2Child = (u8)iChildPtr;
        p->iV2Ptr = iNew;
      }
    }
  }

  return rc;
................................................................................
      u32 iRoot; TreeNode *pRoot; /* New root node */

      pRoot = newTreeNode(pDb, &iRoot, &rc);
      pRoot->aiKeyPtr[1] = pNode->aiKeyPtr[1];
      pRoot->aiChildPtr[1] = iLeft;
      pRoot->aiChildPtr[2] = iRight;

      pDb->treehdr.root.iRoot = iRoot;
      pDb->treehdr.root.nHeight++;
    }else{

      pCsr->iNode--;
      rc = treeInsert(pDb, pCsr, 
          iLeft, pNode->aiKeyPtr[1], iRight, pCsr->aiCell[pCsr->iNode]
      );
    }
................................................................................
  return rc;
}

/*
** Empty the contents of the in-memory tree.
*/
void lsmTreeClear(lsm_db *pDb){
  pDb->treehdr.root.iTransId = 1;
  pDb->treehdr.root.iRoot = 0;
  pDb->treehdr.root.nHeight = 0;
  pDb->treehdr.nByte = 0;
  pDb->treehdr.iUsedShmid = pDb->treehdr.iNextShmid-1;
}

void lsmTreeMakeOld(lsm_db *pDb, int *pnFlush){
  if( pDb->treehdr.iOldShmid ){
    *pnFlush = 2;
  }else{
    *pnFlush = 1;
    pDb->treehdr.iOldLog = pDb->treehdr.log.aRegion[2].iEnd;
    pDb->treehdr.oldcksum0 = pDb->treehdr.log.cksum0;
    pDb->treehdr.oldcksum1 = pDb->treehdr.log.cksum1;
    pDb->treehdr.iOldShmid = pDb->treehdr.iNextShmid-1;
    memcpy(&pDb->treehdr.oldroot, &pDb->treehdr.root, sizeof(TreeRoot));

    pDb->treehdr.root.iTransId = 1;
    pDb->treehdr.root.iRoot = 0;
    pDb->treehdr.root.nHeight = 0;
    pDb->treehdr.nByte = 0;
  }
}

void lsmTreeDiscardOld(lsm_db *pDb){
  assert( lsmShmAssertLock(pDb, LSM_LOCK_WRITER, LSM_LOCK_EXCL) 
       || lsmShmAssertLock(pDb, LSM_LOCK_DMS2, LSM_LOCK_EXCL) 
  );
  pDb->treehdr.iUsedShmid = pDb->treehdr.iOldShmid;
  pDb->treehdr.iOldShmid = 0;
}

int lsmTreeHasOld(lsm_db *pDb){
  return pDb->treehdr.iOldShmid!=0;
}

/*
** This function is called during recovery to initialize the 
** tree header. Only the database connections private copy of the tree-header
** is initialized here - it will be copied into shared memory if log file
** recovery is successful.
*/
int lsmTreeInit(lsm_db *pDb){
  ShmChunk *pOne;
  int rc = LSM_OK;

  pDb->treehdr.root.iTransId = 1;
  pDb->treehdr.iFirst = 1;
  pDb->treehdr.nChunk = 2;
  pDb->treehdr.iWrite = LSM_SHM_CHUNK_SIZE + LSM_SHM_CHUNK_HDR;
  pDb->treehdr.iNextShmid = 2;
  pDb->treehdr.iUsedShmid = 1;

  pOne = treeShmChunkRc(pDb, 1, &rc);
................................................................................
/*
** Iterate through the current in-memory tree. If there are any v2-pointers
** with transaction ids larger than db->treehdr.iTransId, zero them.
*/
static int treeRepairPtrs(lsm_db *db){
  int rc = LSM_OK;

  if( db->treehdr.root.nHeight>1 ){
    TreeCursor csr;               /* Cursor used to iterate through tree */
    u32 iTransId = db->treehdr.root.iTransId;

    /* Initialize the cursor structure. Also decrement the nHeight variable
    ** in the tree-header. This will prevent the cursor from visiting any
    ** leaf nodes.  */
    db->treehdr.root.nHeight--;
    treeCursorInit(db, 0, &csr);

    rc = lsmTreeCursorEnd(&csr, 0);
    while( rc==LSM_OK && lsmTreeCursorValid(&csr) ){
      TreeNode *pNode = csr.apTreeNode[csr.iNode];
      if( pNode->iV2>iTransId ){
        pNode->iV2Child = 0;
        pNode->iV2Ptr = 0;
        pNode->iV2 = 0;
      }
      rc = lsmTreeCursorNext(&csr);
    }
    tblobFree(csr.pDb, &csr.blob);

    db->treehdr.root.nHeight++;
  }

  return rc;
}

static int treeRepairList(lsm_db *db){
  int rc = LSM_OK;
................................................................................
  int nKey,                       /* Size of key data in bytes */
  void *pVal,                     /* Pointer to value data (or NULL) */
  int nVal                        /* Bytes in value data (or -ve for delete) */
){
  int rc = LSM_OK;                /* Return Code */
  TreeKey *pTreeKey;              /* New key-value being inserted */
  u32 iTreeKey;
  TreeRoot *p = &pDb->treehdr.root;

  assert( nVal>=0 || pVal==0 );
  assert_tree_looks_ok(LSM_OK, pTree);
#if 0
  dump_tree_contents(pDb, "before");
#endif

  /* Allocate and populate a new key-value pair structure */
  pTreeKey = newTreeKey(pDb, &iTreeKey, pKey, nKey, pVal, nVal, &rc);
  if( rc!=LSM_OK ) return rc;

  if( p->iRoot==0 ){
    /* The tree is completely empty. Add a new root node and install
    ** (pKey/nKey) as the middle entry. Even though it is a leaf at the
    ** moment, use newTreeNode() to allocate the node (i.e. allocate enough
    ** space for the fields used by interior nodes). This is because the
    ** treeInsert() routine may convert this node to an interior node. */
    TreeNode *pRoot = newTreeNode(pDb, &p->iRoot, &rc);
    if( rc==LSM_OK ){
      assert( p->nHeight==0 );
      pRoot->aiKeyPtr[1] = iTreeKey;
      p->nHeight = 1;
    }
  }else{
    TreeCursor csr;
    int res;

    /* Seek to the leaf (or internal node) that the new key belongs on */
    treeCursorInit(pDb, 0, &csr);
    lsmTreeCursorSeek(&csr, pKey, nKey, &res);

    if( res==0 ){
      /* The search found a match within the tree. */
      TreeNode *pNew;
      u32 iNew;
      TreeNode *pNode = csr.apTreeNode[csr.iNode];
      int iCell = csr.aiCell[csr.iNode];

      /* Create a copy of this node */
      if( (csr.iNode>0 && csr.iNode==(p->nHeight-1)) ){
        pNew = copyTreeLeaf(pDb, (TreeLeaf *)pNode, &iNew, &rc);
      }else{
        pNew = copyTreeNode(pDb, pNode, &iNew, &rc);
      }

      if( rc==LSM_OK ){
        /* Modify the value in the new version */
................................................................................
int lsmTreeSize(lsm_db *pDb){
  return pDb->treehdr.nByte;
}

/*
** Open a cursor on the in-memory tree pTree.
*/
int lsmTreeCursorNew(lsm_db *pDb, int bOld, TreeCursor **ppCsr){
  TreeCursor *pCsr;
  *ppCsr = pCsr = lsmMalloc(pDb->pEnv, sizeof(TreeCursor));
  if( pCsr ){
    treeCursorInit(pDb, bOld, pCsr);
    return LSM_OK;
  }
  return LSM_NOMEM_BKPT;
}

/*
** Close an in-memory tree cursor.
................................................................................
  if( pCsr ){
    tblobFree(pCsr->pDb, &pCsr->blob);
    lsmFree(pCsr->pDb->pEnv, pCsr);
  }
}

void lsmTreeCursorReset(TreeCursor *pCsr){
  if( pCsr ){
    pCsr->iNode = -1;
    pCsr->pSave = 0;
  }
}

#ifndef NDEBUG
static int treeCsrCompare(TreeCursor *pCsr, void *pKey, int nKey){
  TreeKey *p;
  int cmp = 0;
  int rc = LSM_OK;
................................................................................
**     is smaller than the key and set *pRes to -1, or
**
**   * If the tree is empty, leave the cursor at EOF and set *pRes to -1.
*/
int lsmTreeCursorSeek(TreeCursor *pCsr, void *pKey, int nKey, int *pRes){
  int rc = LSM_OK;                /* Return code */
  lsm_db *pDb = pCsr->pDb;
  TreeRoot *pRoot = pCsr->pRoot;
  int (*xCmp)(void *, int, void *, int) = pDb->xCmp;

  u32 iNodePtr;                   /* Location of current node in search */

  /* Discard any saved position data */
  treeCursorRestore(pCsr, 0);

  iNodePtr = pRoot->iRoot;
  if( iNodePtr==0 ){
    /* Either an error occurred or the tree is completely empty. */
    assert( rc!=LSM_OK || pRoot->iRoot==0 );
    *pRes = -1;
    pCsr->iNode = -1;
  }else{
    TreeBlob b = {0, 0};
    int res = 0;                  /* Result of comparison function */
    int iNode = -1;
    while( iNodePtr ){
................................................................................
        res = xCmp((void *)&pTreeKey[1], pTreeKey->nKey, pKey, nKey);
        if( res==0 ){
          pCsr->aiCell[iNode] = iTest;
          break;
        }
      }

      if( iNode<(pRoot->nHeight-1) ){
        iNodePtr = getChildPtr(pNode, pRoot->iTransId, iTest + (res<0));
      }else{
        iNodePtr = 0;
      }
      pCsr->aiCell[iNode] = iTest + (iNodePtr && (res<0));
    }

    *pRes = res;
................................................................................

int lsmTreeCursorNext(TreeCursor *pCsr){
#ifndef NDEBUG
  TreeKey *pK1;
  TreeBlob key1 = {0, 0};
#endif
  lsm_db *pDb = pCsr->pDb;
  TreeRoot *pRoot = pCsr->pRoot;
  const int iLeaf = pRoot->nHeight-1;
  int iCell; 
  int rc = LSM_OK; 
  TreeNode *pNode; 

  /* Restore the cursor position, if required */
  int iRestore = 0;
  treeCursorRestore(pCsr, &iRestore);
................................................................................

  pNode = pCsr->apTreeNode[pCsr->iNode];
  iCell = ++pCsr->aiCell[pCsr->iNode];

  /* If the current node is not a leaf, and the current cell has sub-tree
  ** associated with it, descend to the left-most key on the left-most
  ** leaf of the sub-tree.  */
  if( pCsr->iNode<iLeaf && getChildPtr(pNode, pRoot->iTransId, iCell) ){
    do {
      u32 iNodePtr;
      pCsr->iNode++;
      iNodePtr = getChildPtr(pNode, pRoot->iTransId, iCell);
      pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
      pCsr->apTreeNode[pCsr->iNode] = pNode;
      iCell = pCsr->aiCell[pCsr->iNode] = (pNode->aiKeyPtr[0]==0);
    }while( pCsr->iNode < iLeaf );
  }

  /* Otherwise, the next key is found by following pointer up the tree 
................................................................................

int lsmTreeCursorPrev(TreeCursor *pCsr){
#ifndef NDEBUG
  TreeKey *pK1;
  TreeBlob key1 = {0, 0};
#endif
  lsm_db *pDb = pCsr->pDb;
  TreeRoot *pRoot = pCsr->pRoot;
  const int iLeaf = pRoot->nHeight-1;
  int iCell; 
  int rc = LSM_OK; 
  TreeNode *pNode; 

  /* Restore the cursor position, if required */
  int iRestore = 0;
  treeCursorRestore(pCsr, &iRestore);
................................................................................
  pNode = pCsr->apTreeNode[pCsr->iNode];
  iCell = pCsr->aiCell[pCsr->iNode];
  assert( iCell>=0 && iCell<3 );

  /* If the current node is not a leaf, and the current cell has sub-tree
  ** associated with it, descend to the right-most key on the right-most
  ** leaf of the sub-tree.  */
  if( pCsr->iNode<iLeaf && getChildPtr(pNode, pRoot->iTransId, iCell) ){
    do {
      u32 iNodePtr;
      pCsr->iNode++;
      iNodePtr = getChildPtr(pNode, pRoot->iTransId, iCell);
      pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
      if( rc!=LSM_OK ) break;
      pCsr->apTreeNode[pCsr->iNode] = pNode;
      iCell = 1 + (pNode->aiKeyPtr[2]!=0) + (pCsr->iNode < iLeaf);
      pCsr->aiCell[pCsr->iNode] = iCell;
    }while( pCsr->iNode < iLeaf );
  }
................................................................................
/*
** Move the cursor to the first (bLast==0) or last (bLast!=0) entry in the
** in-memory tree.
*/
int lsmTreeCursorEnd(TreeCursor *pCsr, int bLast){
  lsm_db *pDb = pCsr->pDb;
  TreeHeader *pHdr = &pDb->treehdr;
  TreeRoot *pRoot = pCsr->pRoot;
  int rc = LSM_OK;

  u32 iNodePtr;
  pCsr->iNode = -1;

  /* Discard any saved position data */
  treeCursorRestore(pCsr, 0);

  iNodePtr = pRoot->iRoot;
  while( iNodePtr ){
    int iCell;
    TreeNode *pNode;

    pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
    if( rc ) break;

................................................................................
      iCell = ((pNode->aiKeyPtr[2]==0) ? 2 : 3);
    }else{
      iCell = ((pNode->aiKeyPtr[0]==0) ? 1 : 0);
    }
    pCsr->iNode++;
    pCsr->apTreeNode[pCsr->iNode] = pNode;

    if( pCsr->iNode<pRoot->nHeight-1 ){
      iNodePtr = getChildPtr(pNode, pRoot->iTransId, iCell);
    }else{
      iNodePtr = 0;
    }
    pCsr->aiCell[pCsr->iNode] = iCell - (iNodePtr==0 && bLast);
  }

  return rc;
................................................................................

/*
** Store a mark in *pMark. Later on, a call to lsmTreeRollback() with a
** pointer to the same TreeMark structure may be used to roll the tree
** contents back to their current state.
*/
void lsmTreeMark(lsm_db *pDb, TreeMark *pMark){
  pMark->iRoot = pDb->treehdr.root.iRoot;
  pMark->nHeight = pDb->treehdr.root.nHeight;
  pMark->iWrite = pDb->treehdr.iWrite;
  pMark->nChunk = pDb->treehdr.nChunk;
  pMark->iNextShmid = pDb->treehdr.iNextShmid;
  pMark->iRollback = intArraySize(&pDb->rollback);
}

/*
................................................................................
      pFree->iNext = pDb->treehdr.iFirst;
      pFree->iShmid = iShmid--;
      pDb->treehdr.iFirst = iFree;
    }
  }

  /* Restore the tree-header fields */
  pDb->treehdr.root.iRoot = pMark->iRoot;
  pDb->treehdr.root.nHeight = pMark->nHeight;
  pDb->treehdr.iWrite = pMark->iWrite;
  pDb->treehdr.nChunk = pMark->nChunk;
  pDb->treehdr.iNextShmid = pMark->iNextShmid;
}

/*
** Load the in-memory tree header from shared-memory into pDb->treehdr.
................................................................................
  }
  pShm->bWriter = 0;
  intArrayFree(pDb->pEnv, &pDb->rollback);

  return LSM_OK;
}

    incr nShift [expr $nWrite/4]
  }
  append script "plot $plot1 $plot2 $plot3\n"
  append script $data1
  append script $data2
  append script $data3


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

do_write_test x.png 100 100000 100000 1000 {
  LSM   "mmap=1 multi_proc=0 safety=1" 
  LevelDB leveldb
}

    incr nShift [expr $nWrite/4]
  }
  append script "plot $plot1 $plot2 $plot3\n"
  append script $data1
  append script $data2
  append script $data3


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

do_write_test x.png 180 10000 10000 1000 {
  LSM   "mmap=1 multi_proc=0 safety=1 threads=2 autowork=0" 

}