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SQLite事务并发访问问题？

郝春妮 2022-09-19 阅读 58
sqlitesqlunix系统/运维


 

//描述：执行命令 
void ExecSqlCmd(sqlite3 *db, const char *sql, const char *pszThrdName)
{
  int iRet;
  char *err_msg = 0;
  char buf[1024];

  if ((iRet = sqlite3_exec(db, sql, NULL, 0, &err_msg)) != SQLITE_OK)
  {
    sqlite3_free(err_msg);
    TRACE("%s error, sql=%s\n", pszThrdName, sql);
  }
}

//描述：开始事务处理
int BeginTransaction(sqlite3 *db, const char *pszThrdName)
{
  //return ExecSqlCmd(db, "BEGIN", pszThrdName);
  return ExecSqlCmd(db, "BEGIN IMMEDIATE  TRANSACTION", pszThrdName);
  //ExecSqlCmd(db, "BEGIN EXCLUSIVE  TRANSACTION", pszThrdName);
  //ExecSqlCmd(db, "BEGIN TRANSACTION", pszThrdName);
}


//描述：结束事务处理
void CommitTransaction(sqlite3 *db, const char *pszThrdName)
{
  ExecSqlCmd(db, "COMMIT", pszThrdName);
}


//描述：回滚事务处理
void RollBackTransaction(sqlite3 *db, const char *pszThrdName)
{
  ExecSqlCmd(db, "ROLLBACK", pszThrdName);
} 
  
typedef struct TThrdPara{
  int idx;
  const char *pszThrName;
};
sqlite3 *db = NULL;
void TestTransactionLock(int iThrd, const char *pszThreadName)
{
  sqlite3_stmt *stmt;
  int iRet, iLen;
  char *pszSqliteName = USER_DATA_SQLITE3_PATH"gwooDb";
  char *errmsg = NULL;
  char **results;
  static bool fInit = false;

  if (!fInit)
  {
    fInit = true;
    if ((iRet=sqlite3_open(pszSqliteName, &db)) > 0)
    {
      TRACE("can't open db!\n", sqlite3_errmsg(db));
      sqlite3_close(db);
      return;
    }

    char *sqlCreateTable =  "CREATE TABLE TbReal (StartTime DATETIME,SuccTime DATETIME,SaveTime DATETIME,MtrAddr BLOB, x20000200 BLOB, x20010200 BLOB)";
    iRet = sqlite3_exec(db, sqlCreateTable, 0, 0, &errmsg);
  }

  if (iThrd==1 || iThrd==2) //写数据
  {
    while (1)
    {
      BeginTransaction(db, pszThreadName);
      char *insertSql = "INSERT INTO TbReal (StartTime, SuccTime, SaveTime, MtrAddr, x20000200) \
                VALUES(DATETIME(1551262800, 'unixepoch'), DATETIME(1551263014, 'unixepoch'), DATETIME(1551262800, 'unixepoch'), \"000337448041\",?)";
      if ((iRet=sqlite3_prepare(db, insertSql, -1, &stmt, NULL)) == SQLITE_OK) 
      {
        char szBlob[] = {0x01, 0x03, 0x12, 0x01, 0x0a, 0x12, 0x00, 0x14, 0x12, 0x00, 0x1e };
        sqlite3_bind_blob(stmt, 1, szBlob, sizeof(szBlob), SQLITE_TRANSIENT);
        if ((iRet=sqlite3_step(stmt)) != SQLITE_DONE)
        {
          sqlite3_finalize(stmt);
          CommitTransaction(db, pszThreadName);
          TRACE("ThreadName: %s sqlite3_step error!\n", pszThreadName);
          return;
        }
        TRACE("%s: ", pszThreadName);
        for (int i=0; i<sizeof(szBlob); i++)
          TRACE("%02x ", szBlob[i]);
        TRACE("\n");
      }
      
      sqlite3_finalize(stmt);
      CommitTransaction(db, pszThreadName);
            Sleep(10);
    }
  }
  else if (iThrd==3 || iThrd==4) //读数据
  {
    while (1)
    {
      char *queryFieldx20000200SameDate1 = "SELECT StartTime FROM TbReal WHERE MtrAddr==\"000337448041 \"";
      if (sqlite3_prepare(db, queryFieldx20000200SameDate1, -1, &stmt, 0) == SQLITE_OK)
      {
        BYTE bRdBuf[128]={0};
        if ((iRet=sqlite3_step(stmt)) == SQLITE_ROW)
        {
          if ((iLen=sqlite3_column_bytes(stmt, 0)) > 0)
            memcpy(bRdBuf, sqlite3_column_blob(stmt, 0), iLen);
        }
        TRACE("%s: ", pszThreadName);
        for (int i=0; i<iLen; i++)
          TRACE("%02x ", bRdBuf[i]);
        TRACE("\n");
      }
      sqlite3_finalize(stmt);
            Sleep(10);
    }
  }
} 
  
  
  
TThreadRet TrancsationThread(void* pvArg)
{
  TThrdPara *pTrdPara = (TThrdPara*)pvArg;

  TRACE("TrancsationThread: idx=%d, TrdName=%s\n", pTrdPara->idx, pTrdPara->pszThrName);

  TestTransactionLock(pTrdPara->idx, pTrdPara->pszThrName);

  return 1;
}

void MakeThreadTest()
{
  TThrdPara tTrdPara1, tTrdPara2;

  tTrdPara1.idx = 1;
  tTrdPara1.pszThrName = "线程1";
  NewThread(TrancsationThread,  &tTrdPara1, 8192, THREAD_PRIORITY_NORMAL);
  
  tTrdPara2.idx = 2;
  tTrdPara2.pszThrName = "线程2";
  NewThread(TrancsationThread,  &tTrdPara2, 8192, THREAD_PRIORITY_NORMAL);
  //NewThread(CheckNetThread,  NULL, 8192, THREAD_PRIORITY_NORMAL);
  tTrdPara2.idx = 3;
  tTrdPara2.pszThrName = "线程3";
  NewThread(TrancsationThread,  &tTrdPara2, 8192, THREAD_PRIORITY_NORMAL);
  //NewThread(CheckNetThread,  NULL, 8192, THREAD_PRIORITY_NORMAL);
  tTrdPara2.idx = 4;
  tTrdPara2.pszThrName = "线程4";
  NewThread(TrancsationThread,  &tTrdPara2, 8192, THREAD_PRIORITY_NORMAL);
  //NewThread(CheckNetThread,  NULL, 8192, THREAD_PRIORITY_NORMAL);
  while(1)
  {
    Sleep(1000);
  }
}

int main()
{
  MakeThreadTest();
}

 

未加锁时事务开始、提交出现报错，日志如下

TrancsationThread: idx=1, TrdName=线程1
TrancsationThread: idx=2, TrdName=线程2
线程2 error, iRet=21, sql=BEGIN IMMEDIATE  TRANSACTION, err_msg=(null)
TrancsationThread: idx=3, TrdName=线程3
TrancsationThread: idx=4, TrdName=线程4
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程4: ok
线程1: ok
线程3: ok
线程3: ok
线程2: ok
线程4: ok
线程1: ok
线程4: ok
线程3: ok
线程4: ok
线程2: ok
线程1: ok
线程3: ok
线程4: ok
线程2: ok
线程3: ok
线程1: ok
线程4: ok
线程2: ok
线程3: ok
线程4: ok
线程3: ok
线程1: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程4: ok
线程3: ok
线程4: ok
线程2: ok
线程1: ok
线程3: ok
线程4: ok
线程2: ok
线程4: ok
线程1: ok
线程3: ok
线程4: ok
线程3: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程2: ok
线程4: ok
线程3: ok
线程3: ok
线程4: ok
线程1: ok
线程3: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程4: ok
线程2: ok
线程3: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程3: ok
线程4: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程2: ok
线程4: ok
线程3: ok
线程3: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程3: ok
线程4: ok
线程1: ok
线程2: ok
线程4: ok
线程3: ok
线程3: ok
线程4: ok
线程1: ok
线程3: ok
线程4: ok
线程2: ok
线程1: ok
线程4: ok
线程3: ok
线程3: ok
线程4: ok
线程2: ok
线程3: ok
线程4: ok
线程1: ok
线程2: ok
线程3: ok
线程4: ok
线程1: ok
线程3: ok
线程4: ok
线程3: ok
线程2: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程4: ok
线程1: ok
线程3: ok
线程4: ok
线程3: ok
线程4: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程3: ok
线程2: ok
线程4: ok
线程1: ok
线程3: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程4: ok
线程3: ok
线程2: ok
线程4: ok
线程1: ok
线程3: ok
线程3: ok
线程4: ok
线程2: ok
线程1: ok
线程3: ok
线程4: ok
线程3: ok
线程2: ok
线程1: ok
线程4: ok
线程3: ok
线程4: ok
线程2: ok
线程3: ok
线程4: ok
线程1: ok
线程2: ok
线程4: ok
线程3: ok
线程1: ok
线程4: ok
线程3: ok
线程4: ok
线程2: ok
线程1: ok
线程3: ok
线程4: ok
线程2: ok
线程1: ok
线程4: ok
线程2: ok
线程3: ok
线程1: ok
线程3: ok
线程4: ok

上面代码需增加实物开启的防错机制检测

      if (BeginTransaction(db, pszThreadName) != SQLITE_OK)
      {
        Sleep(10);
        continue;
      }

 

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