Programmer Group

The full name of AQS is AbstractQueued Synchronizer, which is a synchronizer design framework provided by JDK. Many concurrent data structures, such as ReentrantLock, ReentrantReadWriteLock, Semaphore and so on, are implemented based on AQS. Next, the principle of AQS is analyzed.   I. underlying data structure The AQS under ...

Does 51CTO have no directory function?Good or bad ========Welcome to Penguin for any questions ^-^1176738641 ======== preparation in advance folders creating #Create five folders in the user directory app #Storage application software #Store application packages data #Store test data lib #Store jar pa ...

Combiner concept Combiner is known as the local Reduce, and Reduce's input is the final output of Combiner. In MapReduce, when the data generated by map is too large, bandwidth becomes a bottleneck. How to compress the data transmitted to Reduce without affecting the final results? One way is to use Combiner, which is known ...

outline One of the main difficulties of distributed applications is "partial failure". For example, through message middleware, one node in the network sends messages to another node. It is difficult for the sending node to know whether the message is successfully delivered, when it is delivered, whether the receivin ...

GPT-2 is an upgrade of GPT, and focuses more on why pretrain is useful. LM itself is a Multi-task Learner, and ZSL experiment is used to support this idea. Article directory I. Preface II. GPT-2 Principle 1. data set 2. Input characterization 3. model Three. Experiment. IV. Implementation of TensorFlow 1. Model structure 2 ...

Key words: elastic search, crate.io, sql Elastic Search has been introduced before. It has simple deployment, powerful search aggregation function and is integrated with other big data frameworks. It is inconvenient that queries need to be submitted through JSON as request Body. Request response is also JSON. As I am used to using SQL, I can't ...

Sequence diagram 1. NetworkWordCount 2. Initialize StreamingContext 3. Create InputDStream 4. Start Job Scheduler 1. NetworkWordCount package yk.streaming import org.apache.spark.SparkConf import org.apache.spark.storage.StorageLevel import org.apache.spark.streaming.{Seconds, StreamingContext} object NetworkWordCount { ...

1.Yarn Common Commands: [rachel@bigdata-senior01 bin]$ ./yarn Usage: yarn [--config confdir] COMMAND where COMMAND is one of: resourcemanager run the ResourceManager nodemanager run a nodemanager on each slave timelineserver run the timeline server rmadmin admin tools version ...

Spark textfile reads HDFS file partitions [compressed and uncompressed] sc.textFile("/blabla/{*.gz}") When we create spark context and use textfile to read files, what partition is it based on? What is the partition size? Compressed format of files File size and HDFS block size textfile will create a Hadoop RDD that uses ...

I/O Operation of Hadoop: Serialization (I) 1. serialization (1) Basic definitionsSerialization refers to the conversion of structured objects into byte streams for transmission over the network or permanent storage on disk; deserialization refers to the conversion of byte streams back to structured objects. (2) Applications ...