SQLite

#  define uint32 unsigned int
#endif

struct MD5Context {
  int isInit;
  uint32 buf[4];
  uint32 bits[2];

  unsigned char in[64];


};
typedef struct MD5Context MD5Context;

/*
 * Note: this code is harmless on little-endian machines.
 */
static void byteReverse (unsigned char *buf, unsigned longs){

  ctx->bits[1] += len >> 29;

  t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

  /* Handle any leading odd-sized chunks */

  if ( t ) {
    unsigned char *p = (unsigned char *)ctx->in + t;

    t = 64-t;
    if (len < t) {
      memcpy(p, buf, len);
      return;
    }
    memcpy(p, buf, t);
    byteReverse(ctx->in, 16);
    MD5Transform(ctx->buf, (uint32 *)ctx->in);
    buf += t;
    len -= t;
  }

  /* Process data in 64-byte chunks */

  while (len >= 64) {
    memcpy(ctx->in, buf, 64);
    byteReverse(ctx->in, 16);
    MD5Transform(ctx->buf, (uint32 *)ctx->in);
    buf += 64;
    len -= 64;
  }

  /* Handle any remaining bytes of data. */

  memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
static void MD5Final(unsigned char digest[16], MD5Context *ctx){
  unsigned count;
  unsigned char *p;

  /* Compute number of bytes mod 64 */
  count = (ctx->bits[0] >> 3) & 0x3F;

  /* Set the first char of padding to 0x80.  This is safe since there is
     always at least one byte free */
  p = ctx->in + count;
  *p++ = 0x80;

  /* Bytes of padding needed to make 64 bytes */
  count = 64 - 1 - count;

  /* Pad out to 56 mod 64 */
  if (count < 8) {
    /* Two lots of padding:  Pad the first block to 64 bytes */
    memset(p, 0, count);
    byteReverse(ctx->in, 16);
    MD5Transform(ctx->buf, (uint32 *)ctx->in);

    /* Now fill the next block with 56 bytes */
    memset(ctx->in, 0, 56);
  } else {
    /* Pad block to 56 bytes */
    memset(p, 0, count-8);
  }
  byteReverse(ctx->in, 14);

  /* Append length in bits and transform */
  ((uint32 *)ctx->in)[ 14 ] = ctx->bits[0];
  ((uint32 *)ctx->in)[ 15 ] = ctx->bits[1];

  MD5Transform(ctx->buf, (uint32 *)ctx->in);
  byteReverse((unsigned char *)ctx->buf, 4);
  memcpy(digest, ctx->buf, 16);
  memset(ctx, 0, sizeof(*ctx));    /* In case it is sensitive */
}

/*
** Convert a 128-bit MD5 digest into a 32-digit base-16 number.

    { checkpoint_starvation_1, "checkpoint_starvation_1", 10000 },
    { checkpoint_starvation_2, "checkpoint_starvation_2", 10000 },

    { create_drop_index_1, "create_drop_index_1", 10000 },
    { lookaside1,          "lookaside1", 10000 },
    { vacuum1,             "vacuum1", 10000 },
    { stress1,             "stress1", 10000 },
    { stress2,             "stress2", 10000 },
  };

  int i;
  int bTestfound = 0;

  sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
  sqlite3_config(SQLITE_CONFIG_MULTITHREAD);

      closedb(&err, &db);
      opendb(&err, &db, "test.db", 0);
    }
    execsql(&err, &db, "DELETE FROM t1 WHERE (rowid % 4)==:i", &i);
    i1++;
    if( err.rc ) i2++;
    clear_error(&err, SQLITE_LOCKED);
    clear_error(&err, SQLITE_ERROR);
  }
  closedb(&err, &db);
  print_and_free_err(&err);
  return sqlite3_mprintf("deleted from t1 %d/%d attempts", i2, i1);
}

** 10. Big DELETE statements.
** 11. VACUUM.
** 14. Integrity-check.
** 17. Switch the journal mode from delete to wal and back again.
** 19. Open and close database connections rapidly.
*/

#define STRESS2_TABCNT 5




static void stress2_workload1(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb, 
      "CREATE TABLE IF NOT EXISTS t%d(x PRIMARY KEY, y, z);", iTab
  );
}

static void stress2_workload2(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb, "DROP TABLE IF EXISTS t%d;", iTab);
}

static void stress2_workload3(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb, "SELECT * FROM t%d WHERE z = 'small'", iTab);
}

static void stress2_workload4(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb, "SELECT * FROM t%d WHERE z = 'big'", iTab);
}

static void stress2_workload5(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb,
      "INSERT INTO t%d VALUES(random(), hex(randomblob(57)), 'small');", iTab
  );
}

static void stress2_workload6(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb,
      "INSERT INTO t%d VALUES(random(), hex(randomblob(2000)), 'big');", iTab
  );
}

static void stress2_workload7(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb,
      "UPDATE t%d SET y = hex(randomblob(57)) "
      "WHERE (x %% 5)==(%d %% 5) AND z='small';"
      ,iTab, i
  );
}
static void stress2_workload8(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb,
      "UPDATE t%d SET y = hex(randomblob(2000)) "
      "WHERE (x %% 5)==(%d %% 5) AND z='big';"
      ,iTab, i
  );
}

static void stress2_workload9(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb,
      "DELETE FROM t%d WHERE (x %% 5)==(%d %% 5) AND z='small';"
      ,iTab, i
  );
}
static void stress2_workload10(Error *pErr, Sqlite *pDb, int i){
  int iTab = (i % STRESS2_TABCNT);
  sql_script_printf(pErr, pDb,
      "DELETE FROM t%d WHERE (x %% 5)==(%d %% 5) AND z='big';"
      ,iTab, i
  );
}

static void stress2_workload11(Error *pErr, Sqlite *pDb, int i){
  sql_script(pErr, pDb, "VACUUM");
}

static char *stress2_thread_wrapper(int iTid, void *pArg){
  Stress2Ctx *pCtx = (Stress2Ctx*)pArg;
  Error err = {0};                /* Error code and message */
  Sqlite db = {0};                /* SQLite database connection */
  int i1 = 0;
  int i2 = 0;

  opendb(&err, &db, pCtx->zDb, 0);
  while( !timetostop(&err) ){



    pCtx->xProc(&err, &db, i1);
    i2 += (err.rc==SQLITE_OK);
    clear_error(&err, SQLITE_LOCKED);
    clear_error(&err, SQLITE_ERROR);
    i1++;


  }

  print_and_free_err(&err);
  return sqlite3_mprintf("ok %d/%d", i2, i1);
}

static void stress2_launch_thread_loop(

    { stress2_workload8 },
    { stress2_workload9 },
    { stress2_workload10 },
    { stress2_workload11 },
    { stress2_workload14 },
    { stress2_workload17 },
  };
  const char *azDb[] = {
    "test.db",
    "file::memory:?cache=shared"
  };
  int j;

  for(j=0; j<sizeof(azDb)/sizeof(azDb[0]); j++){
    int i;
    Error err = {0};
    Sqlite db = {0};
    Threadset threads = {0};
    const char *zDb = azDb[j];

    /* To make sure the db file is empty before commencing */
    opendb(&err, &db, zDb, 1);




    closedb(&err, &db);

    setstoptime(&err, nMs);
    sqlite3_enable_shared_cache(1);

    for(i=0; i<sizeof(aTask)/sizeof(aTask[0]); i++){
      stress2_launch_thread_loop(&err, &threads, zDb, aTask[i].x);
    }
    launch_thread(&err, &threads, stress2_workload19, (void*)zDb);
    launch_thread(&err, &threads, stress2_workload19, (void*)zDb);

    join_all_threads(&err, &threads);
    sqlite3_enable_shared_cache(0);
    print_and_free_err(&err);
    if( j==0 ){
      printf("Running stress2 (again, with in-memory db) for %d seconds...\n",
          nMs / 1000
      );
    }
  }
}