C运行查询显示命令不同步？

Question

我们正在运行一个C程序，其中每一秒都有一个函数回调。下面的代码列出的片段：

char timeBuf[10],secondBuf1[100],queryBuf1[500],queryBuf2[500]; 
char buff[20] = {0}; 
struct timeval tv; 
gettimeofday (&tv, NULL); 
tv.tv_sec -= 5; 
strftime(buff, 20, "%Y-%m-%d %H:%M:%S", localtime(&tv.tv_sec)); 
printf("\nTime is %s", buff); 

sprintf(secondBuf1,"INSERT INTO secondsLog2 (secondLogID , timeStampID) VALUES (NULL,'%s')",buff); 
//printf("Query 1 before executing %s\n",queryBuf1); 
if (mysql_query(localConn, secondBuf1)) 
{ 
    printf("Error in insert of seconds log %s\n",mysql_error(localConn)); 
    exit(1); 
} 

sprintf(queryBuf1,"SELECT ipDest, portDest, SUM(packetLen), COUNT(ipDest) FROM source1 WHERE timeStamp = '%s' GROUP BY portDest",buff); 
printf("\nQuery buf %s",queryBuf1); 
if(mysql_query(remoteConn, queryBuf1)) 
{ 
    printf("Error in first query of select %s\n",mysql_error(remoteConn)); 
    exit(1); 
} 
localRes1 = mysql_use_result(remoteConn); 
while((localRow1 = mysql_fetch_row(localRes1)) !=NULL) 
      { 
       sprintf(queryBuf1,"INSERT INTO export1 (iBTID ,timeStampID ,ipDest ,portDest,totalBits, packetCount) VALUES (NULL,'%s','%s','%s',%s,%s)",buff, localRow1[0],localRow1[1],localRow1[2],localRow1[3],localRow1[4]); 
       printf("Query 1 before executing %s\n",queryBuf1); 
       if (mysql_query(localConn, queryBuf1)) 
       { 
       printf("Error in first query of insert %s\n",mysql_error(localConn)); 
       exit(1); 
       } 

      } 
         mysql_free_result(localRes1); 

我运行此脚本第二SELECT会给我这个错误的时刻：命令不同步;你现在不能运行此命令：

Time is 2012-07-17 00:59:14 
Query buf SELECT ipDest, portDest, SUM(packetLen), COUNT(ipDest) FROM source1 WHERE timeStamp = '2012-07-17 00:59:14' GROUP BY portDest 
Time is 2012-07-17 00:59:15 
Query buf SELECT ipDest, portDest, SUM(packetLen), COUNT(ipDest) FROM source1 WHERE timeStamp = '2012-07-17 00:59:15' GROUP BY portDestError in first query of select Commands out of sync; you can't run this command now 

Answer 1

你需要清除你的结果上会返回结果有任何疑问设置。如果你不使用的结果的话，只要致电：

MYSQL_RES *results; 
results = mysql_store_result(localConn); 
mysql_free_result(results); 

要使用你的结果只是调用返回的结果，并确保他们在一些点以后使用mysql_free_result查询后mysql_store_result（或mysql_use_result）。这应该会清除与CR_COMMANDS_OUT_OF_SYNC错误有关的任何问题。

从文档mysql_store_result（强调）：

After invoking mysql_query() or mysql_real_query(), you must call mysql_store_result() or mysql_use_result() for every statement that successfully produces a result set (SELECT, SHOW, DESCRIBE, EXPLAIN, CHECK TABLE, and so forth). You must also call mysql_free_result() after you are done with the result set.