使用otl,报错:mysql Commands out of sync; you can't run this command now

时间:2021-07-10 06:39:02

1、代码如下:

void TestCache(otl_connect& otlConn)
{
try
{
char sql[] = {};
sprintf(sql,"call test1(1)");
otl_stream stream(, sql, otlConn,otl_implicit_select); int id;
while(!stream.eof())
{
stream>>id;
char sql2[] = {};
sprintf(sql2,"call test2(:Id<int>)");
otl_stream stream2(, sql2, otlConn,otl_implicit_select);
stream2<<id;
  
       int ff =0;
while(!stream2.eof())
{
stream2>>ff;
}
}
}
catch(otl_exception& ex)
{
printf("ExecuteSql Error, ErrorMsg[%s], Sql[%s]",
ex.msg,
ex.stm_text);
}
}

2、执行otl_stream stream2(100, sql2, otlConn,otl_implicit_select);的时候出错,如下:

Commands out of sync; you can't run this command now

特别注意:如果test1 只返回1条或者0条记录,不会导致这个异常。

3、错误原因:mysql上一次的查询没有将结果集释放掉,又进行下一次的查询。
4、otl:在第一个stream读取期间,第二个stream使用了绑定变量,会导致上面的问题,不知道otl内部是怎么封装的。
5、解决办法:
a、第二个stream不使用绑定变量,如下:

void TestCache(otl_connect& otlConn)
{
try
{
char sql[] = {};
sprintf(sql,"call test1(1)");
otl_stream stream(, sql, otlConn,otl_implicit_select); int id;
while(!stream.eof())
{
stream>>id;
char sql2[] = {};
sprintf(sql2,"call test2(%d)",id);
otl_stream stream2(, sql2, otlConn,otl_implicit_select); int ff =0;
while(!stream2.eof())
{
stream2>>ff;
}
}
}
catch(otl_exception& ex)
{
printf("ExecuteSql Error, ErrorMsg[%s], Sql[%s]",
ex.msg,
ex.stm_text);
}
}

b、先把第一个stream读取完,再进行第二个stream,如下:

void TestCache(otl_connect& otlConn)
{
try
{
char sql[] = {};
sprintf(sql,"call test1(1)");
otl_stream stream(, sql, otlConn,otl_implicit_select); vector<int> intVec;
int id;
while(!stream.eof())
{
stream>>id;
intVec.push_back(id);
} for(vector<int>::iterator iter = intVec.begin();
iter != intVec.end(); ++iter)
{
char sql2[] = {};
sprintf(sql2,"call test2(:Id<int>)");
otl_stream stream2(, sql2, otlConn,otl_implicit_select);
stream2<<id; int ff =0;
while(!stream2.eof())
{
stream>>ff;
}
}
}
catch(otl_exception& ex)
{
printf("ExecuteSql Error, ErrorMsg[%s], Sql[%s]",
ex.msg,
ex.stm_text);
}
}