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Overview
Comment:Fixes for compressed database mode. Some test cases pass. Many do not.
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SHA1: 90c2fae338c8374dd4d028aca769ac3546cdb012
User & Date: dan 2012-10-23 19:54:23
Context
2012-10-24
18:26
Various fixes. check-in: 728d8cf5ae user: dan tags: compression-hooks
2012-10-23
19:54
Fixes for compressed database mode. Some test cases pass. Many do not. check-in: 90c2fae338 user: dan tags: compression-hooks
2012-10-22
20:05
Add some code to support compressed databases to lsm_file.c. Does not currently work. check-in: 3c45b911fe user: dan tags: compression-hooks
Changes
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Changes to lsm-test/lsmtest.h.

    74     74   ** Functions in wrapper3.c. This file contains the tdb wrapper for lsm.
    75     75   ** The wrapper for lsm is a bit more involved than the others, as it 
    76     76   ** includes code for a couple of different lsm configurations, and for
    77     77   ** various types of fault injection and robustness testing.
    78     78   */
    79     79   int test_lsm_open(const char *zFilename, int bClear, TestDb **ppDb);
    80     80   int test_lsm_lomem_open(const char *zFilename, int bClear, TestDb **ppDb);
           81  +int test_lsm_zip_open(const char *zFilename, int bClear, TestDb **ppDb);
    81     82   int test_lsm_small_open(const char *zFilename, int bClear, TestDb **ppDb);
    82     83   int test_lsm_mt2(const char *zFilename, int bClear, TestDb **ppDb);
    83     84   int test_lsm_mt3(const char *zFilename, int bClear, TestDb **ppDb);
    84     85   
    85     86   /* Functions in testutil.c. */
    86     87   int  testPrngInit(void);
    87     88   u32  testPrngValue(u32 iVal);

Changes to lsm-test/lsmtest1.c.

   189    189         memcpy(pKey1, pKey2, nKey1+1);
   190    190         testDatasourceEntry(pData, iKey2, &pKey2, &nKey2, 0, 0);
   191    191   
   192    192         testScanCompare(pDb2, pDb, 0, 0, 0,         0, 0,         &rc);
   193    193         testScanCompare(pDb2, pDb, 0, 0, 0,         pKey2, nKey2, &rc);
   194    194         testScanCompare(pDb2, pDb, 0, pKey1, nKey1, 0, 0,         &rc);
   195    195         testScanCompare(pDb2, pDb, 0, pKey1, nKey1, pKey2, nKey2, &rc);
          196  +#if 0
   196    197         testScanCompare(pDb2, pDb, 1, 0, 0,         0, 0,         &rc);
   197    198         testScanCompare(pDb2, pDb, 1, 0, 0,         pKey2, nKey2, &rc);
   198    199         testScanCompare(pDb2, pDb, 1, pKey1, nKey1, 0, 0,         &rc);
   199    200         testScanCompare(pDb2, pDb, 1, pKey1, nKey1, pKey2, nKey2, &rc);
          201  +#endif
   200    202         testFree(pKey1);
   201    203       }
   202    204       tdb_close(pDb2);
   203    205     }
   204    206   
   205    207     /* Test some lookups. */
   206    208     for(j=0; rc==0 && j<nLookupTest; j++){

Changes to lsm-test/lsmtest_tdb.c.

   609    609     const char *zName;
   610    610     const char *zDefaultDb;
   611    611     int (*xOpen)(const char *zFilename, int bClear, TestDb **ppDb);
   612    612   } aLib[] = {
   613    613     { "sqlite3",      "testdb.sqlite",    sql_open },
   614    614     { "lsm_small",    "testdb.lsm_small", test_lsm_small_open },
   615    615     { "lsm_lomem",    "testdb.lsm_lomem", test_lsm_lomem_open },
          616  +  { "lsm_zip",      "testdb.lsm_zip",   test_lsm_zip_open },
   616    617     { "lsm",          "testdb.lsm",       test_lsm_open },
   617    618   #ifdef LSM_MUTEX_PTHREADS
   618    619     { "lsm_mt2",      "testdb.lsm_mt2",   test_lsm_mt2 },
   619    620     { "lsm_mt3",      "testdb.lsm_mt3",   test_lsm_mt3 },
   620    621   #endif
   621    622   #ifdef HAVE_LEVELDB
   622    623     { "leveldb",      "testdb.leveldb",   test_leveldb_open },

Changes to lsm-test/lsmtest_tdb3.c.

   388    388     sqlite3_free(zFree);
   389    389   }
   390    390   /*
   391    391   ** End test VFS code.
   392    392   **************************************************************************
   393    393   *************************************************************************/
   394    394   
          395  +/*************************************************************************
          396  +**************************************************************************
          397  +** Begin test compression hooks.
          398  +*/
          399  +
          400  +static int testZipBound(void *pCtx, int nSrc){
          401  +  assert( 0 );
          402  +  return 0;
          403  +}
          404  +
          405  +static int testZipCompress(
          406  +  void *pCtx,                    /* Context pointer */
          407  +  char *aOut, int *pnOut,        /* OUT: Buffer containing compressed data */
          408  +  const char *aIn, int nIn       /* Buffer containing input data */
          409  +){
          410  +  assert( 0 );
          411  +  return 0;
          412  +}
          413  +
          414  +static int testZipUncompress(
          415  +  void *pCtx,                    /* Context pointer */
          416  +  char *aOut, int *pnOut,        /* OUT: Buffer containing uncompressed data */
          417  +  const char *aIn, int nIn       /* Buffer containing input data */
          418  +){
          419  +  assert( 0 );
          420  +  return 0;
          421  +}
          422  +
          423  +static int testConfigureCompression(lsm_db *pDb){
          424  +  static lsm_compress zip = {
          425  +    1, sizeof(lsm_compress),
          426  +    0,                            /* Context pointer (unused) */
          427  +    testZipBound,                 /* xBound method */
          428  +    testZipCompress,              /* xCompress method */
          429  +    testZipUncompress             /* xUncompress method */
          430  +  };
          431  +  return lsm_config(pDb, LSM_CONFIG_SET_COMPRESSION, &zip);
          432  +}
          433  +
          434  +/*
          435  +** End test compression hooks.
          436  +**************************************************************************
          437  +*************************************************************************/
          438  +
   395    439   static int test_lsm_close(TestDb *pTestDb){
   396    440     int i;
   397    441     int rc = LSM_OK;
   398    442     LsmDb *pDb = (LsmDb *)pTestDb;
   399    443   
   400    444     lsm_csr_close(pDb->pCsr);
   401    445     lsm_close(pDb->db);
................................................................................
   613    657   static void xWorkHook(lsm_db *db, void *pArg){
   614    658     LsmDb *p = (LsmDb *)pArg;
   615    659     if( p->xWork ) p->xWork(db, p->pWorkCtx);
   616    660   }
   617    661   
   618    662   #define TEST_NO_RECOVERY -1
   619    663   #define TEST_THREADS     -2
          664  +#define TEST_COMPRESSION -3
   620    665   
   621    666   static int test_lsm_config_str(
   622    667     LsmDb *pLsm,
   623    668     lsm_db *db, 
   624    669     int bWorker,
   625    670     const char *zStr,
   626    671     int *pnThread
................................................................................
   641    686       { "use_log",          0, LSM_CONFIG_USE_LOG },
   642    687       { "nmerge",           0, LSM_CONFIG_NMERGE },
   643    688       { "max_freelist",     0, LSM_CONFIG_MAX_FREELIST },
   644    689       { "multi_proc",       0, LSM_CONFIG_MULTIPLE_PROCESSES },
   645    690       { "worker_nmerge",    1, LSM_CONFIG_NMERGE },
   646    691       { "test_no_recovery", 0, TEST_NO_RECOVERY },
   647    692       { "threads",          0, TEST_THREADS },
          693  +    { "compression",      0, TEST_COMPRESSION },
   648    694       { 0, 0 }
   649    695     };
   650    696     const char *z = zStr;
   651    697     int nThread = 1;
   652    698   
   653    699     assert( db );
   654    700     while( z[0] ){
................................................................................
   692    738             switch( eParam ){
   693    739               case TEST_NO_RECOVERY:
   694    740                 pLsm->bNoRecovery = iVal;
   695    741                 break;
   696    742               case TEST_THREADS:
   697    743                 nThread = iVal;
   698    744                 break;
          745  +            case TEST_COMPRESSION:
          746  +              testConfigureCompression(db);
          747  +              break;
   699    748             }
   700    749           }
   701    750         }
   702    751       }else if( z!=zStart ){
   703    752         goto syntax_error;
   704    753       }
   705    754     }
................................................................................
   831    880     int bClear, 
   832    881     TestDb **ppDb
   833    882   ){
   834    883     const char *zCfg = 
   835    884       "page_size=256 block_size=65536 write_buffer=16384 "
   836    885       "max_freelist=4 autocheckpoint=32768 "
   837    886       "mmap=0 "
          887  +  ;
          888  +  return testLsmOpen(zCfg, zFilename, bClear, ppDb);
          889  +}
          890  +
          891  +int test_lsm_zip_open(
          892  +  const char *zFilename, 
          893  +  int bClear, 
          894  +  TestDb **ppDb
          895  +){
          896  +  const char *zCfg = 
          897  +    "page_size=256 block_size=65536 write_buffer=16384 "
          898  +    "max_freelist=4 autocheckpoint=32768 compression=1"
          899  +    "mmap=0 "
   838    900     ;
   839    901     return testLsmOpen(zCfg, zFilename, bClear, ppDb);
   840    902   }
   841    903   
   842    904   lsm_db *tdb_lsm(TestDb *pDb){
   843    905     if( pDb->pMethods->xClose==test_lsm_close ){
   844    906       return ((LsmDb *)pDb)->db;

Changes to src/lsm.h.

   211    211   **
   212    212   **   LSM_CONFIG_MULTIPLE_PROCESSES
   213    213   **     A read/write boolean parameter. This parameter may only be set before
   214    214   **     lsm_open() has been called. If true, the library uses shared-memory
   215    215   **     and posix advisory locks to co-ordinate access by clients from within
   216    216   **     multiple processes. Otherwise, if false, all database clients must be 
   217    217   **     located in the same process. The default value is true.
          218  +**
          219  +**   LSM_CONFIG_SET_COMPRESSION
          220  +**     Set the compression methods used to compress and decompress database
          221  +**     content. The argument to this option should be a pointer to a structure
          222  +**     of type lsm_compress. The lsm_config() method takes a copy of the 
          223  +**     structures contents.
          224  +**
          225  +**     This option may only be used before lsm_open() is called. Invoking it
          226  +**     after lsm_open() has been called results in an LSM_MISUSE error.
          227  +**
          228  +**   LSM_CONFIG_GET_COMPRESSION
          229  +**     Query the compression methods used to compress and decompress database
          230  +**     content.
   218    231   */
   219    232   #define LSM_CONFIG_WRITE_BUFFER        1
   220    233   #define LSM_CONFIG_PAGE_SIZE           2
   221    234   #define LSM_CONFIG_SAFETY              3
   222    235   #define LSM_CONFIG_BLOCK_SIZE          4
   223    236   #define LSM_CONFIG_AUTOWORK            5
   224    237   #define LSM_CONFIG_LOG_SIZE            6
   225    238   #define LSM_CONFIG_MMAP                7
   226    239   #define LSM_CONFIG_USE_LOG             8
   227    240   #define LSM_CONFIG_NMERGE              9
   228    241   #define LSM_CONFIG_MAX_FREELIST       10
   229    242   #define LSM_CONFIG_MULTIPLE_PROCESSES 11
   230    243   #define LSM_CONFIG_AUTOCHECKPOINT     12
          244  +
          245  +#define LSM_CONFIG_SET_COMPRESSION    13
          246  +#define LSM_CONFIG_GET_COMPRESSION    14
   231    247   
   232    248   #define LSM_SAFETY_OFF    0
   233    249   #define LSM_SAFETY_NORMAL 1
   234    250   #define LSM_SAFETY_FULL   2
   235    251   
   236    252   
   237    253   /*

Changes to src/lsmInt.h.

   300    300     int bUseLog;                    /* Configured by LSM_CONFIG_USE_LOG */
   301    301     int nDfltPgsz;                  /* Configured by LSM_CONFIG_PAGE_SIZE */
   302    302     int nDfltBlksz;                 /* Configured by LSM_CONFIG_BLOCK_SIZE */
   303    303     int nMaxFreelist;               /* Configured by LSM_CONFIG_MAX_FREELIST */
   304    304     int bMmap;                      /* Configured by LSM_CONFIG_MMAP */
   305    305     int nAutockpt;                  /* Configured by LSM_CONFIG_AUTOCHECKPOINT */
   306    306     int bMultiProc;                 /* Configured by L_C_MULTIPLE_PROCESSES */
          307  +  lsm_compress compress;          /* Compression callbacks */
   307    308   
   308    309     /* Sub-system handles */
   309    310     FileSystem *pFS;                /* On-disk portion of database */
   310    311     Database *pDatabase;            /* Database shared data */
   311    312   
   312    313     /* Client transaction context */
   313    314     Snapshot *pClient;              /* Client snapshot (non-NULL in read trans) */

Changes to src/lsm_file.c.

   167    167     LsmFile *pLsmFile;
   168    168     lsm_file *fdDb;                 /* Database file */
   169    169     lsm_file *fdLog;                /* Log file */
   170    170   
   171    171     /* If this is a compressed database, a pointer to the compression methods.
   172    172     ** For an uncompressed database, a NULL pointer.  */
   173    173     lsm_compress *pCompress;
          174  +  u8 *aBuffer;                    /* Buffer to compress into */
   174    175   
   175    176     /* mmap() mode things */
   176    177     int bUseMmap;                   /* True to use mmap() to access db file */
   177    178     void *pMap;                     /* Current mapping of database file */
   178    179     i64 nMap;                       /* Bytes mapped at pMap */
   179    180     Page *pFree;
   180    181   
................................................................................
   239    240   
   240    241   /*
   241    242   ** Number of pgsz byte pages omitted from the start of block 1. The start
   242    243   ** of block 1 contains two 4096 byte meta pages (8192 bytes in total).
   243    244   */
   244    245   #define BLOCK1_HDR_SIZE(pgsz)  LSM_MAX(1, 8192/(pgsz))
   245    246   
          247  +/*
          248  +** If NDEBUG is not defined, set a breakpoint in function lsmIoerrBkpt()
          249  +** to catch IO errors. 
          250  +*/
          251  +#ifndef NDEBUG
          252  +static int lsmIoerrBkpt(){
          253  +  static int nErr = 0;
          254  +  nErr++;
          255  +}
          256  +static int IOERR_WRAPPER(int rc){
          257  +  if( rc!=LSM_OK ) lsmIoerrBkpt();
          258  +  return rc;
          259  +}
          260  +#else
          261  +# define IOERR_WRAPPER(rc) (rc)
          262  +#endif
   246    263   
   247    264   /*
   248    265   ** Wrappers around the VFS methods of the lsm_env object:
   249    266   **
   250    267   **     lsmEnvOpen()
   251    268   **     lsmEnvRead()
   252    269   **     lsmEnvWrite()
................................................................................
   263    280   static int lsmEnvRead(
   264    281     lsm_env *pEnv, 
   265    282     lsm_file *pFile, 
   266    283     lsm_i64 iOff, 
   267    284     void *pRead, 
   268    285     int nRead
   269    286   ){
   270         -  return pEnv->xRead(pFile, iOff, pRead, nRead);
          287  +  return IOERR_WRAPPER( pEnv->xRead(pFile, iOff, pRead, nRead) );
   271    288   }
   272    289   static int lsmEnvWrite(
   273    290     lsm_env *pEnv, 
   274    291     lsm_file *pFile, 
   275    292     lsm_i64 iOff, 
   276         -  void *pWrite, 
          293  +  const void *pWrite, 
   277    294     int nWrite
   278    295   ){
   279         -  return pEnv->xWrite(pFile, iOff, pWrite, nWrite);
          296  +  return IOERR_WRAPPER( pEnv->xWrite(pFile, iOff, (void *)pWrite, nWrite) );
   280    297   }
   281    298   static int lsmEnvSync(lsm_env *pEnv, lsm_file *pFile){
   282         -  return pEnv->xSync(pFile);
          299  +  return IOERR_WRAPPER( pEnv->xSync(pFile) );
   283    300   }
   284    301   static int lsmEnvSectorSize(lsm_env *pEnv, lsm_file *pFile){
   285    302     return pEnv->xSectorSize(pFile);
   286    303   }
   287    304   int lsmEnvClose(lsm_env *pEnv, lsm_file *pFile){
   288         -  return pEnv->xClose(pFile);
          305  +  return IOERR_WRAPPER( pEnv->xClose(pFile) );
   289    306   }
   290    307   static int lsmEnvTruncate(lsm_env *pEnv, lsm_file *pFile, lsm_i64 nByte){
   291         -  return pEnv->xTruncate(pFile, nByte);
          308  +  return IOERR_WRAPPER( pEnv->xTruncate(pFile, nByte) );
   292    309   }
   293    310   static int lsmEnvUnlink(lsm_env *pEnv, const char *zDel){
   294         -  return pEnv->xUnlink(pEnv, zDel);
          311  +  return IOERR_WRAPPER( pEnv->xUnlink(pEnv, zDel) );
   295    312   }
   296    313   static int lsmEnvRemap(
   297    314     lsm_env *pEnv, 
   298    315     lsm_file *pFile, 
   299    316     i64 szMin,
   300    317     void **ppMap,
   301    318     i64 *pszMap
................................................................................
   453    470       pFS->zLog = &pFS->zDb[nDb+1];
   454    471       pFS->nPagesize = LSM_DFLT_PAGE_SIZE;
   455    472       pFS->nBlocksize = LSM_DFLT_BLOCK_SIZE;
   456    473       pFS->nMetasize = 4 * 1024;
   457    474       pFS->pDb = pDb;
   458    475       pFS->pEnv = pDb->pEnv;
   459    476       pFS->bUseMmap = pDb->bMmap;
          477  +    if( pDb->compress.xCompress ){
          478  +      pFS->pCompress = &pDb->compress;
          479  +    }
   460    480   
   461    481       /* Make a copy of the database and log file names. */
   462    482       memcpy(pFS->zDb, zDb, nDb+1);
   463    483       memcpy(pFS->zLog, zDb, nDb);
   464    484       memcpy(&pFS->zLog[nDb], "-log", 5);
   465    485   
   466    486       /* Allocate the hash-table here. At some point, it should be changed
................................................................................
   585    605   void lsmFsSetBlockSize(FileSystem *pFS, int nBlocksize){
   586    606     pFS->nBlocksize = nBlocksize;
   587    607   }
   588    608   
   589    609   /*
   590    610   ** Return the page number of the first page on block iBlock. Blocks are
   591    611   ** numbered starting from 1.
          612  +**
          613  +** For a compressed database, page numbers are byte offsets. The first
          614  +** page on each block is the byte offset immediately following the 4-byte
          615  +** "previous block" pointer at the start of each block.
   592    616   */
   593    617   static Pgno fsFirstPageOnBlock(FileSystem *pFS, int iBlock){
   594    618     Pgno iPg;
   595    619     if( pFS->pCompress ){
   596    620       if( iBlock==1 ){
   597         -      iPg = pFS->nMetasize * 2;
          621  +      iPg = pFS->nMetasize * 2 + 4;
   598    622       }else{
   599         -      iPg = pFS->nBlocksize * (Pgno)(iBlock-1);
          623  +      iPg = pFS->nBlocksize * (Pgno)(iBlock-1) + 4;
   600    624       }
   601    625     }else{
   602    626       const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
   603    627       if( iBlock==1 ){
   604    628         iPg = 1 + ((pFS->nMetasize*2 + pFS->nPagesize - 1) / pFS->nPagesize);
   605    629       }else{
   606    630         iPg = 1 + (iBlock-1) * nPagePerBlock;
................................................................................
   608    632     }
   609    633     return iPg;
   610    634   }
   611    635   
   612    636   /*
   613    637   ** Return the page number of the last page on block iBlock. Blocks are
   614    638   ** numbered starting from 1.
          639  +**
          640  +** For a compressed database, page numbers are byte offsets. The first
          641  +** page on each block is the byte offset of the byte immediately before 
          642  +** the 4-byte "next block" pointer at the end of each block.
   615    643   */
   616    644   static Pgno fsLastPageOnBlock(FileSystem *pFS, int iBlock){
   617    645     if( pFS->pCompress ){
   618         -    return pFS->nBlocksize * (Pgno)iBlock - 1;
          646  +    return pFS->nBlocksize * (Pgno)iBlock - 1 - 4;
   619    647     }else{
   620    648       const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
   621    649       return iBlock * nPagePerBlock;
   622    650     }
   623    651   }
   624    652   
          653  +/*
          654  +** Return the block number of the block that page iPg is located on. 
          655  +** Blocks are numbered starting from 1.
          656  +*/
   625    657   static int fsPageToBlock(FileSystem *pFS, Pgno iPg){
   626    658     if( pFS->pCompress ){
   627    659       return (iPg / pFS->nBlocksize) + 1;
   628    660     }else{
   629    661       return 1 + ((iPg-1) / (pFS->nBlocksize / pFS->nPagesize));
   630    662     }
   631    663   }
   632    664   
   633    665   /*
   634    666   ** Return true if page iPg is the last page on its block.
          667  +**
          668  +** This function is only called in non-compressed database mode.
   635    669   */
   636    670   static int fsIsLast(FileSystem *pFS, Pgno iPg){
   637         -  if( pFS->pCompress ){
   638         -    assert( 0 );
   639         -    return 0;
   640         -  }else{
   641         -    const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
   642         -    return ( iPg && (iPg % nPagePerBlock)==0 );
   643         -  }
          671  +  const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
          672  +  assert( !pFS->pCompress );
          673  +  return ( iPg && (iPg % nPagePerBlock)==0 );
   644    674   }
   645    675   
   646    676   /*
   647    677   ** Return true if page iPg is the first page on its block.
          678  +**
          679  +** This function is only called in non-compressed database mode.
   648    680   */
   649    681   static int fsIsFirst(FileSystem *pFS, Pgno iPg){
   650         -  if( pFS->pCompress ){
   651         -    assert( 0 );
   652         -    return 0;
   653         -  }else{
   654         -    const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
   655         -    return (
   656         -        (iPg % nPagePerBlock)==1
          682  +  const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
          683  +  assert( !pFS->pCompress );
          684  +
          685  +  return ( (iPg % nPagePerBlock)==1
   657    686           || (iPg<nPagePerBlock && iPg==fsFirstPageOnBlock(pFS, 1))
   658         -    );
   659         -  }
          687  +  );
   660    688   }
   661    689   
   662    690   /*
   663    691   ** Given a page reference, return a pointer to the in-memory buffer of the
   664    692   ** pages contents. If parameter pnData is not NULL, set *pnData to the size
   665    693   ** of the buffer in bytes before returning.
   666    694   */
................................................................................
   798    826           pFix->aData = &aData[pFS->nPagesize * (i64)(pFix->iPg-1)];
   799    827         }
   800    828         lsmSortedRemap(pFS->pDb);
   801    829       }
   802    830       *pRc = rc;
   803    831     }
   804    832   }
          833  +
          834  +static int fsPageGet(FileSystem *, Pgno, int, Page **);
          835  +
          836  +/*
          837  +** Parameter iBlock is a database file block. This function reads the value 
          838  +** stored in the blocks "next block" pointer and stores it in *piNext.
          839  +** LSM_OK is returned if everything is successful, or an LSM error code
          840  +** otherwise.
          841  +*/
          842  +static int fsBlockNext(
          843  +  FileSystem *pFS,                /* File-system object handle */
          844  +  int iBlock,                     /* Read field from this block */
          845  +  int *piNext                     /* OUT: Next block in linked list */
          846  +){
          847  +  int rc;
          848  +
          849  +  assert( pFS->bUseMmap==0 || pFS->pCompress==0 );
          850  +  if( pFS->pCompress ){
          851  +    i64 iOff;                     /* File offset to read data from */
          852  +    u8 aNext[4];                  /* 4-byte pointer read from db file */
          853  +
          854  +    iOff = (i64)iBlock * pFS->nBlocksize - sizeof(aNext);
          855  +    rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aNext, sizeof(aNext));
          856  +    if( rc==LSM_OK ){
          857  +      *piNext = (int)lsmGetU32(aNext);
          858  +    }
          859  +  }else{
          860  +    const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
          861  +    Page *pLast;
          862  +    rc = fsPageGet(pFS, iBlock*nPagePerBlock, 0, &pLast);
          863  +    if( rc==LSM_OK ){
          864  +      *piNext = fsPageToBlock(pFS, lsmGetU32(&pLast->aData[pFS->nPagesize-4]));
          865  +      lsmFsPageRelease(pLast);
          866  +    }
          867  +  }
          868  +  return rc;
          869  +}
   805    870   
   806    871   /*
   807    872   ** This function is only called in compressed database mode.
   808    873   */
   809    874   static int fsReadData(
   810    875     FileSystem *pFS,                /* File-system handle */
   811    876     i64 iOff,                       /* Read data from this offset */
   812    877     u8 *aData,                      /* Buffer to read data into */
   813    878     int nData                       /* Number of bytes to read */
   814    879   ){
   815    880     i64 iEob;                       /* End of block */
   816    881     int nRead;
          882  +  int rc;
   817    883   
   818    884     assert( pFS->pCompress );
   819    885   
   820    886     iEob = fsLastPageOnBlock(pFS, fsPageToBlock(pFS, iOff)) + 1;
   821         -  nRead = LSM_MAX(iEob - iOff, nData);
          887  +  nRead = LSM_MIN(iEob - iOff, nData);
   822    888   
   823    889     rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aData, nRead);
   824    890     if( rc==LSM_OK && nRead!=nData ){
   825    891       int iBlk;
   826    892   
   827    893       rc = fsBlockNext(pFS, fsPageToBlock(pFS, iOff), &iBlk);
   828    894       if( rc==LSM_OK ){
   829    895         i64 iOff2 = fsFirstPageOnBlock(pFS, iBlk);
   830         -      rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, &aData[nRead], nData-nRead);
          896  +      rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff2, &aData[nRead], nData-nRead);
   831    897       }
   832    898     }
   833    899   
   834    900     return rc;
   835    901   }
   836    902   
   837    903   /*
................................................................................
   843    909   */
   844    910   static int fsReadPagedata(
   845    911     FileSystem *pFS,                /* File-system handle */
   846    912     Page *pPg                       /* Page to read and uncompress data for */
   847    913   ){
   848    914     i64 iOff;
   849    915     u8 aVarint[9];
          916  +  int rc;
   850    917   
   851    918     assert( pFS->pCompress && pPg->nCompress==0 );
   852    919   
   853    920     iOff = pPg->iPg;
   854    921     rc = fsReadData(pFS, iOff, aVarint, sizeof(aVarint));
   855    922     if( rc==LSM_OK ){
   856    923       iOff += lsmVarintGet32(aVarint, &pPg->nCompress);
................................................................................
   909    976       if( p==0 ){
   910    977         rc = fsPageBuffer(pFS, 1, &p);
   911    978         if( rc==LSM_OK ){
   912    979           p->iPg = iPg;
   913    980           p->nRef = 0;
   914    981           p->pFS = pFS;
   915    982           assert( p->flags==0 || p->flags==PAGE_FREE );
   916         -        if( fsIsLast(pFS, iPg) || fsIsFirst(pFS, iPg) ) p->flags |= PAGE_SHORT;
          983  +        if( pFS->pCompress==0 && (fsIsLast(pFS, iPg) || fsIsFirst(pFS, iPg)) ){
          984  +          p->flags |= PAGE_SHORT;
          985  +        }
   917    986   
   918    987   #ifdef LSM_DEBUG
   919    988           memset(p->aData, 0x56, pFS->nPagesize);
   920    989   #endif
   921    990           assert( p->pLruNext==0 && p->pLruPrev==0 );
   922    991           if( noContent==0 ){
   923    992             if( pFS->pCompress ){
................................................................................
   982   1051     }else{
   983   1052       assert( 0 );
   984   1053     }
   985   1054     return rc;
   986   1055   }
   987   1056   
   988   1057   
   989         -/*
   990         -** Parameter iBlock is a database file block. This function reads the value 
   991         -** stored in the blocks "next block" pointer and stores it in *piNext.
   992         -** LSM_OK is returned if everything is successful, or an LSM error code
   993         -** otherwise.
   994         -*/
   995         -static int fsBlockNext(
   996         -  FileSystem *pFS,                /* File-system object handle */
   997         -  int iBlock,                     /* Read field from this block */
   998         -  int *piNext                     /* OUT: Next block in linked list */
   999         -){
  1000         -  int rc;
  1001         -
  1002         -  assert( pFS->bUseMmap==0 || pFS->pCompress==0 );
  1003         -  if( pFS->pCompress ){
  1004         -    i64 iOff = (i64)iBlock * pFS->nBlocksize - sizeof(aNext);
  1005         -    u8 aNext[4];                  /* 4-byte pointer read from db file */
  1006         -    rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iOff, aNext, sizeof(aNext));
  1007         -    if( rc==LSM_OK ){
  1008         -      *piNext = (int)lsmGetU32(aNext);
  1009         -    }
  1010         -  }else{
  1011         -    const int nPagePerBlock = (pFS->nBlocksize / pFS->nPagesize);
  1012         -    Page *pLast;
  1013         -    rc = fsPageGet(pFS, iBlock*nPagePerBlock, 0, &pLast);
  1014         -    if( rc==LSM_OK ){
  1015         -      *piNext = fsPageToBlock(pFS, lsmGetU32(&pLast->aData[pFS->nPagesize-4]));
  1016         -      lsmFsPageRelease(pLast);
  1017         -    }
  1018         -  }
  1019         -  return rc;
  1020         -}
  1021         -
  1022   1058   static int fsRunEndsBetween(
  1023   1059     Segment *pRun, 
  1024   1060     Segment *pIgnore, 
  1025   1061     Pgno iFirst, 
  1026   1062     Pgno iLast
  1027   1063   ){
  1028   1064     return (pRun!=pIgnore && (
................................................................................
  1185   1221     int nByte;
  1186   1222   
  1187   1223     assert( pFS->pCompress );
  1188   1224   
  1189   1225     iEob = 1 + fsLastPageOnBlock(pFS, fsPageToBlock(pFS, iPg));
  1190   1226     nByte = 2 * lsmVarintLen32(pPg->nCompress) + pPg->nCompress;
  1191   1227   
  1192         -  if( (iPg + nByte)<=iEob && (iPg + nByte - 1)==pSeg->iLastPg ){
         1228  +  if( pSeg && (iPg + nByte)<=iEob && (iPg + nByte - 1)==pSeg->iLastPg ){
  1193   1229       *piNext = 0;
  1194   1230     }else if( (iPg + nByte)>=iEob ){
  1195   1231       int iNext;
  1196   1232       Pgno iNextPg;
  1197   1233   
  1198   1234       rc = fsBlockNext(pFS, fsPageToBlock(pFS, iPg), &iNext);
  1199   1235       iNextPg = fsFirstPageOnBlock(pFS, iNext) + (nByte - (iEob-iPg));
  1200         -    if( pSeg->iLastPg==(iNextPg-1) ){
         1236  +    if( pSeg && pSeg->iLastPg==(iNextPg-1) ){
  1201   1237         iNextPg = 0;
  1202   1238       }
  1203   1239       *piNext = iNextPg;
  1204   1240     }else{
  1205   1241       *piNext = iPg + nByte;
  1206   1242     }
  1207   1243   
................................................................................
  1233   1269     FileSystem *pFS = pPg->pFS;
  1234   1270     Pgno iPg = pPg->iPg;
  1235   1271   
  1236   1272     if( pFS->pCompress ){
  1237   1273       if( eDir<0 ){
  1238   1274         assert( 0 );
  1239   1275       }else{
  1240         -      rc = fsNextPageOffset(pRun, pPg, &iPg);
         1276  +      int rc = fsNextPageOffset(pRun, pPg, &iPg);
         1277  +      if( rc!=LSM_OK || iPg==0 ){
         1278  +        *ppNext = 0;
         1279  +        return rc;
         1280  +      }
  1241   1281       }
  1242   1282     }else{
  1243   1283       assert( eDir==1 || eDir==-1 );
  1244   1284       if( eDir<0 ){
  1245   1285         if( pRun && iPg==pRun->iFirst ){
  1246   1286           *ppNext = 0;
  1247   1287           return LSM_OK;
................................................................................
  1290   1330     int rc = LSM_OK;
  1291   1331     Page *pPg = 0;
  1292   1332     *ppOut = 0;
  1293   1333     int iApp = 0;
  1294   1334     int iNext = 0;
  1295   1335     int iPrev = p->iLastPg;
  1296   1336   
  1297         -  if( iPrev==0 ){
  1298         -    iApp = findAppendPoint(pFS);
  1299         -  }else if( fsIsLast(pFS, iPrev) ){
  1300         -    int iNext;
  1301         -    rc = fsBlockNext(pFS, fsPageToBlock(pFS, iPrev), &iNext);
  1302         -    if( rc!=LSM_OK ) return rc;
  1303         -    iApp = fsFirstPageOnBlock(pFS, iNext);
         1337  +  if( pFS->pCompress ){
         1338  +    /* In compressed database mode the page is not assigned a page number
         1339  +    ** or location in the database file at this point. This will be done
         1340  +    ** by the lsmFsPagePersist() call.  */
         1341  +    rc = fsPageBuffer(pFS, 1, &pPg);
         1342  +    if( rc==LSM_OK ){
         1343  +      pPg->pFS = pFS;
         1344  +      pPg->pSeg = p;
         1345  +      pPg->iPg = 0;
         1346  +      pPg->flags = PAGE_DIRTY;
         1347  +      pPg->nData = pFS->nPagesize;
         1348  +      assert( pPg->aData );
         1349  +
         1350  +      pPg->nRef = 1;
         1351  +      pFS->nOut++;
         1352  +    }
  1304   1353     }else{
  1305         -    iApp = iPrev + 1;
  1306         -  }
  1307         -
  1308         -  /* If this is the first page allocated, or if the page allocated is the
  1309         -   ** last in the block, allocate a new block here.  */
  1310         -  if( iApp==0 || fsIsLast(pFS, iApp) ){
  1311         -    int iNew;                     /* New block number */
  1312         -
  1313         -    lsmBlockAllocate(pFS->pDb, &iNew);
  1314         -    if( iApp==0 ){
  1315         -      iApp = fsFirstPageOnBlock(pFS, iNew);
         1354  +    if( iPrev==0 ){
         1355  +      iApp = findAppendPoint(pFS);
         1356  +    }else if( fsIsLast(pFS, iPrev) ){
         1357  +      int iNext;
         1358  +      rc = fsBlockNext(pFS, fsPageToBlock(pFS, iPrev), &iNext);
         1359  +      if( rc!=LSM_OK ) return rc;
         1360  +      iApp = fsFirstPageOnBlock(pFS, iNext);
  1316   1361       }else{
  1317         -      iNext = fsFirstPageOnBlock(pFS, iNew);
  1318         -    }
  1319         -  }
  1320         -
  1321         -  /* Grab the new page. */
  1322         -  pPg = 0;
  1323         -  rc = fsPageGet(pFS, iApp, 1, &pPg);
  1324         -  assert( rc==LSM_OK || pPg==0 );
  1325         -
  1326         -  /* If this is the first or last page of a block, fill in the pointer 
  1327         -   ** value at the end of the new page. */
  1328         -  if( rc==LSM_OK ){
  1329         -    p->nSize++;
  1330         -    p->iLastPg = iApp;
  1331         -    if( p->iFirst==0 ) p->iFirst = iApp;
  1332         -    pPg->flags |= PAGE_DIRTY;
  1333         -
  1334         -    if( fsIsLast(pFS, iApp) ){
  1335         -      lsmPutU32(&pPg->aData[pFS->nPagesize-4], iNext);
  1336         -    }else 
  1337         -      if( fsIsFirst(pFS, iApp) ){
  1338         -        lsmPutU32(&pPg->aData[pFS->nPagesize-4], iPrev);
  1339         -      }
         1362  +      iApp = iPrev + 1;
         1363  +    }
         1364  +
         1365  +    /* If this is the first page allocated, or if the page allocated is the
         1366  +     ** last in the block, allocate a new block here.  */
         1367  +    if( iApp==0 || fsIsLast(pFS, iApp) ){
         1368  +      int iNew;                     /* New block number */
         1369  +
         1370  +      lsmBlockAllocate(pFS->pDb, &iNew);
         1371  +      if( iApp==0 ){
         1372  +        iApp = fsFirstPageOnBlock(pFS, iNew);
         1373  +      }else{
         1374  +        iNext = fsFirstPageOnBlock(pFS, iNew);
         1375  +      }
         1376  +    }
         1377  +
         1378  +    /* Grab the new page. */
         1379  +    pPg = 0;
         1380  +    rc = fsPageGet(pFS, iApp, 1, &pPg);
         1381  +    assert( rc==LSM_OK || pPg==0 );
         1382  +
         1383  +    /* If this is the first or last page of a block, fill in the pointer 
         1384  +     ** value at the end of the new page. */
         1385  +    if( rc==LSM_OK ){
         1386  +      p->nSize++;
         1387  +      p->iLastPg = iApp;
         1388  +      if( p->iFirst==0 ) p->iFirst = iApp;
         1389  +      pPg->flags |= PAGE_DIRTY;
         1390  +
         1391  +      if( fsIsLast(pFS, iApp) ){
         1392  +        lsmPutU32(&pPg->aData[pFS->nPagesize-4], iNext);
         1393  +      }else 
         1394  +        if( fsIsFirst(pFS, iApp) ){
         1395  +          lsmPutU32(&pPg->aData[pFS->nPagesize-4], iPrev);
         1396  +        }
         1397  +    }
  1340   1398     }
  1341   1399   
  1342   1400     *ppOut = pPg;
  1343   1401     return rc;
  1344   1402   }
  1345   1403   
  1346   1404   /*
................................................................................
  1384   1442   /*
  1385   1443   ** Obtain a reference to page number iPg.
  1386   1444   */
  1387   1445   int lsmFsDbPageGet(FileSystem *pFS, Pgno iPg, Page **ppPg){
  1388   1446     assert( pFS );
  1389   1447     return fsPageGet(pFS, iPg, 0, ppPg);
  1390   1448   }
         1449  +
         1450  +static int fsReadReverseVarint32(FileSystem *pFS, Pgno iPg, int *pnVal){
         1451  +  int rc;
         1452  +  Pgno iFirst;
         1453  +
         1454  +  iFirst = fsFirstPageOnBlock(pFS, fsPageToBlock(pFS, iPg));
         1455  +  if( (iPg - iFirst)<4 ){
         1456  +    int nRead = 4 + (1 + iPg - iFirst);
         1457  +    u8 aRead[5 + 4];              /* Space for varint + ptr */
         1458  +    rc = lsmEnvRead(pFS->pEnv, pFS->fdDb, iFirst-4, aRead, nRead);
         1459  +
         1460  +  }else{
         1461  +    u8 aRead[5];                  /* Space for varint + ptr */
         1462  +
         1463  +    rc = lsmEnvRead(
         1464  +        pFS->pEnv, pFS->fdDb, iPg+1-sizeof(aRead), aRead, sizeof(aRead)
         1465  +    );
         1466  +
         1467  +    if( aRead[4]<=240 ){
         1468  +      *pnVal = aRead[4];
         1469  +    }else if( aRead[4]<=248 ){
         1470  +      *pnVal = 240 + 256 * (aRead[4]-241) + aRead[3];
         1471  +    }else{
         1472  +      *pnVal = ((int)(aRead[1])<<16) + ((int)(aRead[2])<<8) + (int)(aRead[3]);
         1473  +      if( aRead[4]==250 ) *pnVal += (((int)aRead[0]) << 24);
         1474  +    }
         1475  +
         1476  +  }
         1477  +  return rc;
         1478  +}
  1391   1479   
  1392   1480   /*
  1393   1481   ** Obtain a reference to the last page in the segment passed as the 
  1394   1482   ** second argument.
  1395   1483   */
  1396   1484   int lsmFsDbPageLast(FileSystem *pFS, Segment *pSeg, Page **ppPg){
  1397   1485     Pgno iLast = pSeg->iLastPg;
  1398   1486     if( pFS->pCompress ){
  1399         -    assert( 0 );
         1487  +    int nCompress;
         1488  +    rc = fsReadReverseVarint32(pFS, iLast, &nCompress);
  1400   1489     }
  1401   1490     return fsPageGet(pFS, iLast, 0, ppPg);
  1402   1491   }
  1403   1492   
  1404   1493   /*
  1405   1494   ** Return a reference to meta-page iPg. If successful, LSM_OK is returned
  1406   1495   ** and *ppPg populated with the new page reference. The reference should
................................................................................
  1514   1603     if( rc==LSM_OK ){
  1515   1604       int nRem;
  1516   1605       int nWrite;
  1517   1606       Pgno iApp = pSeg->iLastPg+1;
  1518   1607   
  1519   1608       /* If this is the first data written into the segment, find an append-point
  1520   1609       ** or allocate a new block.  */
  1521         -    if( iApp==0 ){
  1522         -      iApp = findAppendPoint(pFS);
  1523         -    }
  1524         -    if( iApp==0 ){
  1525         -      int iBlk;
  1526         -      rc = lsmBlockAllocate(pFS->pDb, &iBlk);
  1527         -      iApp = fsFirstPageOnBlock(pFS, iBlk);
         1610  +    if( iApp==1 ){
         1611  +      pSeg->iFirst = iApp = findAppendPoint(pFS);
         1612  +      if( iApp==0 ){
         1613  +        int iBlk;
         1614  +        rc = lsmBlockAllocate(pFS->pDb, &iBlk);
         1615  +        pSeg->iFirst = iApp = fsFirstPageOnBlock(pFS, iBlk);
         1616  +      }
  1528   1617       }
  1529   1618   
  1530   1619       iRet = iApp;
  1531   1620   
  1532   1621       /* Write as much data as is possible at iApp (usually all of it). */
  1533   1622       if( rc==LSM_OK ){
  1534         -      int nSpace = fsLastPageOnBlock(pFS, fsPageToBlock(iApp)) - iApp - 1;
  1535         -      nWrite = LSM_MAX(nData, nSpace);
         1623  +      int nSpace = fsLastPageOnBlock(pFS, fsPageToBlock(pFS, iApp)) - iApp + 1;
         1624  +      nWrite = LSM_MIN(nData, nSpace);
  1536   1625         nRem = nData - nWrite;
  1537   1626         rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iApp, aData, nWrite);
  1538   1627   
  1539   1628         iApp += nWrite;
  1540   1629       }
  1541   1630   
  1542   1631       /* If required, allocate a new block and write the rest of the data
................................................................................
  1610   1699   */
  1611   1700   int lsmFsPagePersist(Page *pPg){
  1612   1701     int rc = LSM_OK;
  1613   1702     if( pPg && (pPg->flags & PAGE_DIRTY) ){
  1614   1703       FileSystem *pFS = pPg->pFS;
  1615   1704   
  1616   1705       if( pFS->pCompress ){
         1706  +      int iHash;                  /* Hash key of assigned page number */
  1617   1707         u8 aVarint[10];             /* pPg->nCompress as a varint */
  1618   1708         int nVarint;                /* Length of varint stored in aVarint[] */
  1619   1709         assert( pPg->pSeg && pPg->iPg==0 && pPg->nCompress==0 );
  1620   1710   
  1621   1711         /* Compress the page image. */
  1622   1712         rc = fsCompressIntoBuffer(pFS, pPg);
  1623   1713   
  1624   1714         /* Serialize the compressed size into buffer aVarint[] */
  1625   1715         nVarint = lsmVarintPut64(aVarint, pPg->nCompress);
  1626   1716         aVarint[nVarint] = aVarint[0];
  1627   1717   
  1628   1718         /* Write the serialized page record into the database file. */
  1629         -      pPg->iPg = fsAppendData(pSeg, aVarint, nVarint, &rc);
  1630         -      fsAppendData(pSeg, pFS->aBuffer, pPg->nCompress, &rc);
  1631         -      fsAppendData(pSeg, &aVarint[1], nVarint, &rc);
         1719  +      pPg->iPg = fsAppendData(pFS, pPg->pSeg, aVarint, nVarint, &rc);
         1720  +      fsAppendData(pFS, pPg->pSeg, pFS->aBuffer, pPg->nCompress, &rc);
         1721  +      fsAppendData(pFS, pPg->pSeg, &aVarint[1], nVarint, &rc);
         1722  +
         1723  +      /* Now that it has a page number, insert the page into the hash table */
         1724  +      iHash = fsHashKey(pFS->nHash, pPg->iPg);
         1725  +      pPg->pHashNext = pFS->apHash[iHash];
         1726  +      pFS->apHash[iHash] = pPg;
         1727  +
         1728  +      pPg->pSeg->nSize += (nVarint * 2) + pPg->nCompress;
  1632   1729   
  1633   1730       }else{
  1634   1731         i64 iOff;                   /* Offset to write within database file */
  1635   1732         iOff = (i64)pFS->nPagesize * (i64)(pPg->iPg-1);
  1636   1733         if( pFS->bUseMmap==0 ){
  1637   1734           rc = lsmEnvWrite(pFS->pEnv, pFS->fdDb, iOff, pPg->aData,pFS->nPagesize);
  1638   1735         }else if( pPg->flags & PAGE_FREE ){
................................................................................
  1859   1956   ** This function also checks that there are no references to blocks with
  1860   1957   ** out-of-range block numbers.
  1861   1958   **
  1862   1959   ** If no errors are found, non-zero is returned. If an error is found, an
  1863   1960   ** assert() fails.
  1864   1961   */
  1865   1962   int lsmFsIntegrityCheck(lsm_db *pDb){
  1866         -  int i;
  1867         -  int j;
  1868         -  Freelist freelist = {0, 0, 0};
  1869   1963     FileSystem *pFS = pDb->pFS;
  1870         -  u8 *aUsed;
  1871         -  Level *pLevel;
  1872         -  Snapshot *pWorker = pDb->pWorker;
  1873         -  int nBlock = pWorker->nBlock;
  1874         -
  1875         -  aUsed = lsmMallocZero(pDb->pEnv, nBlock);
  1876         -  if( aUsed==0 ){
  1877         -    /* Malloc has failed. Since this function is only called within debug
  1878         -    ** builds, this probably means the user is running an OOM injection test.
  1879         -    ** Regardless, it will not be possible to run the integrity-check at this
  1880         -    ** time, so assume the database is Ok and return non-zero. */
  1881         -    return 1;
  1882         -  }
  1883         -
  1884         -  for(pLevel=pWorker->pLevel; pLevel; pLevel=pLevel->pNext){
         1964  +  if( pFS->pCompress==0 ){
  1885   1965       int i;
  1886         -    checkBlocks(pFS, &pLevel->lhs, (pLevel->nRight!=0), nBlock, aUsed);
  1887         -    for(i=0; i<pLevel->nRight; i++){
  1888         -      checkBlocks(pFS, &pLevel->aRhs[i], 0, nBlock, aUsed);
         1966  +    int j;
         1967  +    Freelist freelist = {0, 0, 0};
         1968  +    u8 *aUsed;
         1969  +    Level *pLevel;
         1970  +    Snapshot *pWorker = pDb->pWorker;
         1971  +    int nBlock = pWorker->nBlock;
         1972  +
         1973  +    aUsed = lsmMallocZero(pDb->pEnv, nBlock);
         1974  +    if( aUsed==0 ){
         1975  +      /* Malloc has failed. Since this function is only called within debug
         1976  +       ** builds, this probably means the user is running an OOM injection test.
         1977  +       ** Regardless, it will not be possible to run the integrity-check at this
         1978  +       ** time, so assume the database is Ok and return non-zero. */
         1979  +      return 1;
         1980  +    }
         1981  +
         1982  +    for(pLevel=pWorker->pLevel; pLevel; pLevel=pLevel->pNext){
         1983  +      int i;
         1984  +      checkBlocks(pFS, &pLevel->lhs, (pLevel->nRight!=0), nBlock, aUsed);
         1985  +      for(i=0; i<pLevel->nRight; i++){
         1986  +        checkBlocks(pFS, &pLevel->aRhs[i], 0, nBlock, aUsed);
         1987  +      }
         1988  +    }
         1989  +
         1990  +    if( pWorker->nFreelistOvfl ){
         1991  +      int rc = lsmCheckpointOverflowLoad(pDb, &freelist);
         1992  +      assert( rc==LSM_OK || rc==LSM_NOMEM );
         1993  +      if( rc!=LSM_OK ) return 1;
         1994  +    }
         1995  +
         1996  +    for(j=0; j<2; j++){
         1997  +      Freelist *pFreelist;
         1998  +      if( j==0 ) pFreelist = &pWorker->freelist;
         1999  +      if( j==1 ) pFreelist = &freelist;
         2000  +
         2001  +      for(i=0; i<pFreelist->nEntry; i++){
         2002  +        u32 iBlk = pFreelist->aEntry[i].iBlk;
         2003  +        assert( iBlk<=nBlock );
         2004  +        assert( aUsed[iBlk-1]==0 );
         2005  +        aUsed[iBlk-1] = 1;
         2006  +      }
  1889   2007       }
         2008  +
         2009  +    for(i=0; i<nBlock; i++) assert( aUsed[i]==1 );
         2010  +
         2011  +    lsmFree(pDb->pEnv, aUsed);
         2012  +    lsmFree(pDb->pEnv, freelist.aEntry);
  1890   2013     }
  1891   2014   
  1892         -  if( pWorker->nFreelistOvfl ){
  1893         -    int rc = lsmCheckpointOverflowLoad(pDb, &freelist);
  1894         -    assert( rc==LSM_OK || rc==LSM_NOMEM );
  1895         -    if( rc!=LSM_OK ) return 1;
  1896         -  }
  1897         -
  1898         -  for(j=0; j<2; j++){
  1899         -    Freelist *pFreelist;
  1900         -    if( j==0 ) pFreelist = &pWorker->freelist;
  1901         -    if( j==1 ) pFreelist = &freelist;
  1902         -
  1903         -    for(i=0; i<pFreelist->nEntry; i++){
  1904         -      u32 iBlk = pFreelist->aEntry[i].iBlk;
  1905         -      assert( iBlk<=nBlock );
  1906         -      assert( aUsed[iBlk-1]==0 );
  1907         -      aUsed[iBlk-1] = 1;
  1908         -    }
  1909         -  }
  1910         -
  1911         -  for(i=0; i<nBlock; i++) assert( aUsed[i]==1 );
  1912         -
  1913         -  lsmFree(pDb->pEnv, aUsed);
  1914         -  lsmFree(pDb->pEnv, freelist.aEntry);
  1915   2015     return 1;
  1916   2016   }
  1917   2017   
  1918   2018   #ifndef NDEBUG
  1919   2019   /*
  1920   2020   ** Return true if pPg happens to be the last page in segment pSeg. Or false
  1921   2021   ** otherwise. This function is only invoked as part of assert() conditions.
  1922   2022   */
  1923   2023   int lsmFsDbPageIsLast(Segment *pSeg, Page *pPg){
  1924   2024     if( pPg->pFS->pCompress ){
  1925   2025       Pgno iNext = 0;
  1926         -    rc = fsNextPageOffset(pSeg, pPg, &iNext);
         2026  +    int rc = fsNextPageOffset(pSeg, pPg, &iNext);
  1927   2027       return (rc!=LSM_OK || iNext==0);
  1928   2028     }
  1929   2029     return (pPg->iPg==pSeg->iLastPg);
  1930   2030   }
  1931   2031   #endif

Changes to src/lsm_main.c.

   319    319           ** in multi-process mode.  */
   320    320           *piVal = lsmDbMultiProc(pDb);
   321    321         }else{
   322    322           pDb->bMultiProc = *piVal = (*piVal!=0);
   323    323         }
   324    324         break;
   325    325       }
          326  +
          327  +    case LSM_CONFIG_SET_COMPRESSION: {
          328  +      int *p = va_arg(ap, lsm_compress *);
          329  +      if( pDb->pDatabase ){
          330  +        /* If lsm_open() has been called, this call is against the rules. */
          331  +        rc = LSM_MISUSE_BKPT;
          332  +      }else{
          333  +        memcpy(&pDb->compress, p, sizeof(lsm_compress));
          334  +      }
          335  +      break;
          336  +    }
          337  +
          338  +    case LSM_CONFIG_GET_COMPRESSION: {
          339  +      int *p = va_arg(ap, lsm_compress *);
          340  +      memcpy(p, &pDb->compress, sizeof(lsm_compress));
          341  +      break;
          342  +    }
   326    343   
   327    344       default:
   328    345         rc = LSM_MISUSE;
   329    346         break;
   330    347     }
   331    348   
   332    349     va_end(ap);

Changes to src/lsm_sorted.c.

  1599   1599     */
  1600   1600   #if 0
  1601   1601     assert( assertKeyLocation(pCsr, pPtr, pKey, nKey) );
  1602   1602   #endif
  1603   1603   
  1604   1604     assert( pPtr->nCell>0 
  1605   1605          || pPtr->pSeg->nSize==1 
  1606         -       || lsmFsDbPageIsLast(pPtr->pPg, pPtr->pSeg)
         1606  +       || lsmFsDbPageIsLast(pPtr->pSeg, pPtr->pPg)
  1607   1607     );
  1608   1608     if( pPtr->nCell==0 ){
  1609   1609       segmentPtrReset(pPtr);
  1610   1610     }else{
  1611   1611       iMin = 0;
  1612   1612       iMax = pPtr->nCell-1;
  1613   1613   
................................................................................
  3322   3322     int rc = LSM_OK;                /* Return code */
  3323   3323     Page *pNext = 0;                /* New page appended to run */
  3324   3324     lsm_db *pDb = pMW->pDb;         /* Database handle */
  3325   3325     Segment *pSeg;                  /* Run to append to */
  3326   3326   
  3327   3327     pSeg = &pMW->pLevel->lhs;
  3328   3328     rc = lsmFsSortedAppend(pDb->pFS, pDb->pWorker, pSeg, &pNext);
  3329         -  assert( rc!=LSM_OK || pSeg->iFirst>0 );
         3329  +  assert( rc!=LSM_OK || pSeg->iFirst>0 || pMW->pDb->compress.xCompress );
  3330   3330   
  3331   3331     if( rc==LSM_OK ){
  3332   3332       u8 *aData;                    /* Data buffer belonging to page pNext */
  3333   3333       int nData;                    /* Size of aData[] in bytes */
  3334   3334   
  3335   3335       rc = mergeWorkerPersistAndRelease(pMW);
  3336   3336   
................................................................................
  3860   3860     if( rc==LSM_OK ){
  3861   3861       if( pDel ) pDel->iRoot = 0;
  3862   3862     }else{
  3863   3863       lsmDbSnapshotSetLevel(pDb->pWorker, pNext);
  3864   3864       sortedFreeLevel(pDb->pEnv, pNew);
  3865   3865     }
  3866   3866   
  3867         -#if 0
  3868         -  lsmSortedDumpStructure(pDb, pDb->pWorker, 1, 0, "new-toplevel");
         3867  +#if 1
         3868  +  lsmSortedDumpStructure(pDb, pDb->pWorker, 0, 0, "new-toplevel");
  3869   3869   #endif
  3870   3870   
  3871   3871     if( rc==LSM_OK ){
  3872   3872       assertBtreeOk(pDb, &pNew->lhs);
  3873   3873       sortedInvokeWorkHook(pDb);
  3874   3874     }
  3875   3875   
................................................................................
  4264   4264   
  4265   4265         /* Clean up the MergeWorker object initialized above. If no error
  4266   4266         ** has occurred, invoke the work-hook to inform the application that
  4267   4267         ** the database structure has changed. */
  4268   4268         mergeWorkerShutdown(&mergeworker, &rc);
  4269   4269         if( rc==LSM_OK ) sortedInvokeWorkHook(pDb);
  4270   4270   
  4271         -#if 0
  4272         -      lsmSortedDumpStructure(pDb, pDb->pWorker, 1, 0, "work");
         4271  +#if 1
         4272  +      lsmSortedDumpStructure(pDb, pDb->pWorker, 0, 0, "work");
  4273   4273   #endif
  4274   4274         assertBtreeOk(pDb, &pLevel->lhs);
  4275   4275         assertRunInOrder(pDb, &pLevel->lhs);
  4276   4276   
  4277   4277         /* If bFlush is true and the database is no longer considered "full",
  4278   4278         ** break out of the loop even if nRemaining is still greater than
  4279   4279         ** zero. The caller has an in-memory tree to flush to disk.  */