mongodb:如何在 mongodb shell 上调试 map/reduce [英] mongodb: how to debug map/reduce on mongodb shell

问题描述

我是 MongoDB 新手，我正在使用 map/reduce.有人可以告诉我如何在使用 map/reduce 时进行调试吗?我使用了print()"函数，但在 MongoDB shell 上，没有打印任何内容.以下是我的 reduce 函数:

I am new to MongoDB, I am using map/reduce. Can somebody tell me how to debug while using map/reduce? I used "print()" function but on MongoDB shell, nothing is printed. Following is my reduce function:

    var reduce = function(key, values){
        var result = {count: 0, host: ""};

        for(var i in values){
        result.count++;
        result.host = values[i].host;
        print(key+" : "+values[i]);
        }
        return result;
    }

当我在 shell 上编写上述函数并在完成后按 Enter 时，shell 上没有打印任何内容.还有什么我应该做的调试吗?

when I write the above function on shell and the press Enter after completing, nothing gets printed on the shell. Is there anything else I should do to debug?

谢谢

推荐答案

看来reduce函数中的print()语句是写入日志文件的，而不是shell.因此，请检查您的日志文件以获取调试输出.

It seems that print() statements in reduce functions are written to the log file, rather than the shell. So check your log file for your debug output.

可以在启动mongod进程时使用--logpath D:path olog.txt参数指定日志文件.

You can specify the log file by using a --logpath D:path olog.txt parameter when starting the mongod process.

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