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7 min readTo convert a JSON string to a HashMap in Rust, you can use the serde_json crate. First, add serde_json as a dependency in your Cargo.toml file. Then, parse the JSON string using serde_json::from_str() function to deserialize it into a serde_json::Value type. Finally, use Value::as_object() method to convert the serde_json::Value into a HashMap<String, Value>. Make sure to handle any errors that may occur during the parsing process.
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5 min readIn Hadoop streaming, you can skip failed map tasks by using the -D mapreduce.map.failures.maxpercent parameter. This parameter allows you to specify the maximum percentage of failed map tasks that can occur before the job is considered a failure. You can set this parameter to a value between 0 and 100 to determine how many failed map tasks are acceptable before the job is deemed unsuccessful.
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7 min readWhen sharing objects between Rust and C++, it is important to ensure that the memory management and data structures are compatible between the two languages. One common approach is to use a Foreign Function Interface (FFI) to define and expose functions that can be called from both Rust and C++. This involves declaring the functions in a shared header file that can be included in both languages.
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6 min readTo find memory used by a particular job in Hadoop, you can use the Hadoop Job History Server. Navigate to the Job History Server web interface and search for the particular job you are interested in. Once you have located the job, you can view detailed information about the job including memory usage. Look for metrics such as the amount of memory used by each task and the overall memory usage for the job. This information can help you analyze and optimize the memory usage of your Hadoop jobs.
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8 min readTo create a C++ object from Rust, you can use foreign function interfaces (FFI) to communicate between the two languages. This involves defining an interface in Rust that uses the extern keyword to specify that the function will be called by C or C++, and then calling that function from C++ code.To do this, you need to define a function in Rust that instantiates the object and returns a pointer to it. You can then call this function from C++ and use the returned pointer to access the object.
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4 min readTo override the default sorting of Hadoop, you can define a custom comparator class and specify it in your MapReduce job configuration. This custom comparator class should extend the WritableComparator class and implement the compare method according to your desired sorting logic. You can then set this custom comparator class as the sorting comparator in your job configuration using the setSortComparatorClass method.
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3 min readTo transpose a vector of vectors in Rust, you can use the izip method from the itertools crate along with the collect method. First, import the izip method from the itertools crate. Then, zip the vectors together using izip and collect the result into a new vector of vectors. This will swap the rows and columns of the original vector of vectors, effectively transposing it.[rating:0b8e1296-57d4-4b0a-aae7-729a6718baf4]How to declare a vector of vectors in Rust.
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6 min readTo unzip a file in Hadoop, you can use the Hadoop File System (HDFS) command line tools. First, you need to upload the zipped file to your Hadoop cluster using the HDFS command. Once the file is uploaded, you can use the HDFS command to unzip the file.
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5 min readIn Rust, you can get the local time zone name by using the chrono crate. First, you need to add "chrono" to your dependencies in your Cargo.toml file. Then, you can use the chrono::Local::now().timezone() method to get the local time zone name. This method returns a TimeZone object, which has a name() method that will give you the local time zone name.
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9 min readWhen setting up a Hadoop installation, it is common to encounter warnings that may need to be addressed in order to ensure proper functionality. Some common warnings include issues with network connectivity, configuration settings, and compatibility with specific software versions.To fix warnings in a Hadoop installation, it is important to carefully review the error messages and logs to identify the root cause of the problem.
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5 min readTo fill a Rust function pointer from C++, you would first need to define a function in Rust that you want to call from C++. This function should be marked as extern "C" to expose it as a C-compatible function.Next, in your C++ code, you can declare a function pointer that matches the signature of your Rust function. Then, you can assign this function pointer to the address of the Rust function using the ::std::mem::transmute function.