text: /*
  ** 2014 December 9
  **
  ** The author disclaims copyright to this source code.  In place of
  ** a legal notice, here is a blessing:
  **
  **    May you do good and not evil.
  **    May you find forgiveness for yourself and forgive others.
  **    May you share freely, never taking more than you give.
  **
  *************************************************************************
  **
  **
  */
  
  
  /*
  ** Thread 1. CREATE and DROP a table.
  */
  static char *stress_thread_1(int iTid, void *pArg){
    Error err = {0};                /* Error code and message */
    Sqlite db = {0};                /* SQLite database connection */
  
    opendb(&err, &db, "test.db", 0);
    while( !timetostop(&err) ){
      sql_script(&err, &db, "CREATE TABLE IF NOT EXISTS t1(a PRIMARY KEY, b)");
      clear_error(&err, SQLITE_LOCKED);
      sql_script(&err, &db, "DROP TABLE IF EXISTS t1");
      clear_error(&err, SQLITE_LOCKED);
    }
    closedb(&err, &db);
    print_and_free_err(&err);
    return sqlite3_mprintf("ok");
  }
  
  /*
  ** Thread 2. Open and close database connections.
  */
  static char *stress_thread_2(int iTid, void *pArg){
    Error err = {0};                /* Error code and message */
    Sqlite db = {0};                /* SQLite database connection */
    while( !timetostop(&err) ){
      opendb(&err, &db, "test.db", 0);
      sql_script(&err, &db, "SELECT * FROM sqlite_schema;");
      clear_error(&err, SQLITE_LOCKED);
      closedb(&err, &db);
    }
    print_and_free_err(&err);
    return sqlite3_mprintf("ok");
  }
  
  /*
  ** Thread 3. Attempt many small SELECT statements.
  */
  static char *stress_thread_3(int iTid, void *pArg){
    Error err = {0};                /* Error code and message */
    Sqlite db = {0};                /* SQLite database connection */
  
    int i1 = 0;
    int i2 = 0;
  
    opendb(&err, &db, "test.db", 0);
    while( !timetostop(&err) ){
      sql_script(&err, &db, "SELECT * FROM t1 ORDER BY a;");
      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("read t1 %d/%d attempts", i2, i1);
  }
  
  /*
  ** Thread 5. Attempt INSERT statements.
  */
  static char *stress_thread_4(int iTid, void *pArg){
    Error err = {0};                /* Error code and message */
    Sqlite db = {0};                /* SQLite database connection */
    int i1 = 0;
    int i2 = 0;
    int iArg = PTR2INT(pArg);
  
    opendb(&err, &db, "test.db", 0);
    while( !timetostop(&err) ){
      if( iArg ){
        closedb(&err, &db);
        opendb(&err, &db, "test.db", 0);
      }
      sql_script(&err, &db, 
          "WITH loop(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM loop LIMIT 200) "
          "INSERT INTO t1 VALUES(randomblob(60), randomblob(60));"
      );
      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("wrote t1 %d/%d attempts", i2, i1);
  }
  
  /*
  ** Thread 6. Attempt DELETE operations.
  */
  static char *stress_thread_5(int iTid, void *pArg){
    Error err = {0};                /* Error code and message */
    Sqlite db = {0};                /* SQLite database connection */
    int iArg = PTR2INT(pArg);
  
    int i1 = 0;
    int i2 = 0;
  
    opendb(&err, &db, "test.db", 0);
    while( !timetostop(&err) ){
      i64 i = (i1 % 4);
      if( iArg ){
        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);
    }
    closedb(&err, &db);
    print_and_free_err(&err);
    return sqlite3_mprintf("deleted from t1 %d/%d attempts", i2, i1);
  }
  
  
  static void stress1(int nMs){
    Error err = {0};
    Threadset threads = {0};
  
    setstoptime(&err, nMs);
    sqlite3_enable_shared_cache(1);
  
    launch_thread(&err, &threads, stress_thread_1, 0);
    launch_thread(&err, &threads, stress_thread_1, 0);
  
    launch_thread(&err, &threads, stress_thread_2, 0);
    launch_thread(&err, &threads, stress_thread_2, 0);
  
    launch_thread(&err, &threads, stress_thread_3, 0);
    launch_thread(&err, &threads, stress_thread_3, 0);
  
    launch_thread(&err, &threads, stress_thread_4, 0);
    launch_thread(&err, &threads, stress_thread_4, 0);
  
    launch_thread(&err, &threads, stress_thread_5, 0);
    launch_thread(&err, &threads, stress_thread_5, (void*)1);
  
    join_all_threads(&err, &threads);
    sqlite3_enable_shared_cache(0);
  
    print_and_free_err(&err);
  }
  
  /**************************************************************************
  ***************************************************************************
  ** Start of test case "stress2"
  */
  
  
  
  /*
  ** 1.  CREATE TABLE statements.
  ** 2.  DROP TABLE statements.
  ** 3.  Small SELECT statements.
  ** 4.  Big SELECT statements.
  ** 5.  Small INSERT statements.
  ** 6.  Big INSERT statements.
  ** 7.  Small UPDATE statements.
  ** 8.  Big UPDATE statements.
  ** 9.  Small DELETE statements.
  ** 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          /* count1 in SDS test */
  
  #define STRESS2_COUNT2 200        /* count2 in SDS test */
  #define STRESS2_COUNT3  57        /* count2 in SDS test */
  
  static void stress2_workload1(Error *pErr, Sqlite *pDb, int i){
    int iTab = (i % (STRESS2_TABCNT-1)) + 1;
    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-1)) + 1;
    sql_script_printf(pErr, pDb, "DROP TABLE IF EXISTS t%d;", iTab);
  }
  
  static void stress2_workload3(Error *pErr, Sqlite *pDb, int i){
    sql_script(pErr, pDb, "SELECT * FROM t0 WHERE z = 'small'");
  }
  
  static void stress2_workload4(Error *pErr, Sqlite *pDb, int i){
    sql_script(pErr, pDb, "SELECT * FROM t0 WHERE z = 'big'");
  }
  
  static void stress2_workload5(Error *pErr, Sqlite *pDb, int i){
    sql_script(pErr, pDb,
        "INSERT INTO t0 VALUES(hex(random()), hex(randomblob(200)), 'small');"
    );
  }
  
  static void stress2_workload6(Error *pErr, Sqlite *pDb, int i){
    sql_script(pErr, pDb,
        "INSERT INTO t0 VALUES(hex(random()), hex(randomblob(57)), 'big');"
    );
  }
  
  static void stress2_workload7(Error *pErr, Sqlite *pDb, int i){
    sql_script_printf(pErr, pDb,
        "UPDATE t0 SET y = hex(randomblob(200)) "
        "WHERE x LIKE hex((%d %% 5)) AND z='small';"
        ,i
    );
  }
  static void stress2_workload8(Error *pErr, Sqlite *pDb, int i){
    sql_script_printf(pErr, pDb,
        "UPDATE t0 SET y = hex(randomblob(57)) "
        "WHERE x LIKE hex(%d %% 5) AND z='big';"
        ,i
    );
  }
  
  static void stress2_workload9(Error *pErr, Sqlite *pDb, int i){
    sql_script_printf(pErr, pDb,
        "DELETE FROM t0 WHERE x LIKE hex(%d %% 5) AND z='small';", i
    );
  }
  static void stress2_workload10(Error *pErr, Sqlite *pDb, int i){
    sql_script_printf(pErr, pDb,
        "DELETE FROM t0 WHERE x LIKE hex(%d %% 5) AND z='big';", i
    );
  }
  
  static void stress2_workload11(Error *pErr, Sqlite *pDb, int i){
    sql_script(pErr, pDb, "VACUUM");
  }
  
  static void stress2_workload14(Error *pErr, Sqlite *pDb, int i){
    sql_script(pErr, pDb, "PRAGMA integrity_check");
  }
  
  static void stress2_workload17(Error *pErr, Sqlite *pDb, int i){
    sql_script_printf(pErr, pDb, 
        "PRAGMA journal_mode = %q", (i%2) ? "delete" : "wal"
    );
  }
  
  static char *stress2_workload19(int iTid, void *pArg){
    Error err = {0};                /* Error code and message */
    Sqlite db = {0};                /* SQLite database connection */
    const char *zDb = (const char*)pArg;
    while( !timetostop(&err) ){
      opendb(&err, &db, zDb, 0);
      sql_script(&err, &db, "SELECT * FROM sqlite_schema;");
      clear_error(&err, SQLITE_LOCKED);
      closedb(&err, &db);
    }
    print_and_free_err(&err);
    return sqlite3_mprintf("ok");
  }
  
  
  typedef struct Stress2Ctx Stress2Ctx;
  struct Stress2Ctx {
    const char *zDb;
    void (*xProc)(Error*, Sqlite*, int);
  };
  
  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;
  
    while( !timetostop(&err) ){
      int cnt;
      opendb(&err, &db, pCtx->zDb, 0);
      for(cnt=0; err.rc==SQLITE_OK && cnt<STRESS2_TABCNT; cnt++){
        pCtx->xProc(&err, &db, i1);
        i2 += (err.rc==SQLITE_OK);
        clear_error(&err, SQLITE_LOCKED);
        i1++;
      }
      closedb(&err, &db);
    }
  
    print_and_free_err(&err);
    return sqlite3_mprintf("ok %d/%d", i2, i1);
  }
  
  static void stress2_launch_thread_loop(
    Error *pErr,                    /* IN/OUT: Error code */
    Threadset *pThreads,            /* Thread set */
    const char *zDb,                /* Database name */
    void (*x)(Error*,Sqlite*,int)   /* Run this until error or timeout */
  ){
    Stress2Ctx *pCtx = sqlite3_malloc(sizeof(Stress2Ctx));
    pCtx->zDb = zDb;
    pCtx->xProc = x;
    launch_thread(pErr, pThreads, stress2_thread_wrapper, (void*)pCtx);
  }
  
  static void stress2(int nMs){
    struct Stress2Task {
      void (*x)(Error*,Sqlite*,int);
    } aTask[] = {
      { stress2_workload1 },
      { stress2_workload2 },
      { stress2_workload3 },
      { stress2_workload4 },
      { stress2_workload5 },
      { stress2_workload6 },
      { stress2_workload7 },
      { stress2_workload8 },
      { stress2_workload9 },
      { stress2_workload10 },
      { stress2_workload11 },
      { stress2_workload14 },
      { stress2_workload17 },
    };
    const char *zDb = "test.db";
  
    int i;
    Error err = {0};
    Sqlite db = {0};
    Threadset threads = {0};
  
    /* To make sure the db file is empty before commencing */
    opendb(&err, &db, zDb, 1);
    sql_script(&err, &db, 
        "CREATE TABLE IF NOT EXISTS t0(x PRIMARY KEY, y, z);"
        "CREATE INDEX IF NOT EXISTS i0 ON t0(y);"
    );
    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);
  }
  