The collection mainly has list, set, Tuple, map, etc., we follow the hands-on practical way to learn. We create a list instance in the Eclipse IDE: Now let's look at the code implementation: In the source code, it is stated that the internal is the method of apply to complete the instantiation; In the same way we can instantiate set: You can also see the implementation of the set instantiation object at this point: Next we'll look at the set in the command-line terminal, first of all set:
5. Apply method and Singleton object in Scala to create a new class: As an additional point, the methods placed in object objects are static methods, as follows: Next look at the use of the Apply method: The above code always when we use "val a = Applytest ()" will cause the call of the Apply method and return the value of the method call, that is, the instantiated object of the applytest. C The lass can also be used by the Apply method, as shown in the following ways: Because the methods
Copy an object The content of the copied "input" folder is as follows: The content of the "conf" file under the hadoop installation directory is the same. Now, run the wordcount program in the pseudo-distributed mode we just built: After the operation is complete, let's check the output result: Some statistical results are as follows: At this time, we will go to the hadoop Web console and find that we have submitted and successfully run the task: After hadoop co
This article, it is necessary to read, write well. But after looking, don't forget to check out the Apache Spark website. Because this article understanding or with the source code, official documents inconsistent. A little mistake! "The Cnblogs Code Editor does not support Scala, so the language keyword is not highlighted"In data analysis, processing Key,value pair data is a very common scenario, for example, we can group, aggregate, or combine two o
Jobs that users submit through different threads can run concurrently, but are subject to resource constraints. Job to the dispatch pool (pool) To request resources, the dispatch pool will be based on the project configuration, decide which scheduling mode to use.
FIFO mode by default, the Spark Scheduler Dispatches job execution in FIFO (first-in first Out) mode. Each job is cut into multiple stage. The first job takes all available resources, and
First half Source: http://blog.csdn.net/lsshlsw/article/details/51213610
The latter part is my optimization plan for everyone's reference.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Sparksql Shuffle the error caused by the operation
Org.apache.spark.shuffle.MetadataFetchFailedException:
Missing An output location for shuffle 0
Org.apache.spark.shuffle.FetchFailedException:
Failed to connect to hostname/192.168.xx.xxx:50268
Error from Rdd's shuf
Reprinted from http://www.csdn.net/article/2015-06-08/2824889http://www.zhihu.com/question/26568496Now, Spark has been widely recognized and supported at home: In 2014, spark Summit China in Beijing, the scene is hot, the same year, Spark Meetup in Beijing, Shanghai, Shenzhen and Hangzhou four cities, of which only Beijing has successfully held 5 times, The conte
Contents of this issue:1 Spark streaming Alternative online experiment2 instantly understand the nature of spark streamingQ: Why cut into spark source version from spark streaming?
Spark did not start with spark streamin
Below is a look at the use of Union:Use the collect operation to see the results of the execution:Then look at the use of Groupbykey:Execution Result:The join operation is the process of a Cartesian product operation, as shown in the following example:To perform a join operation on RDD3 and RDD4:Use collect to view execution results:It can be seen that the join operation is exactly a Cartesian product operation;The reduce itself, which is an action-type operation in an RDD operation, causes the
Copy an objectThe content of the copied "input" folder is as follows:The content of the "conf" file under the hadoop installation directory is the same.Now, run the wordcount program in the pseudo-distributed mode we just built:After the operation is complete, let's check the output result:Some statistical results are as follows:At this time, we will go to the hadoop Web console and find that we have submitted and successfully run the task:After hadoop completes the task, you can disable the had
SOURCE Link: Spark streaming: The upstart of large-scale streaming data processingSummary: Spark Streaming is the upstart of large-scale streaming data processing, which decomposes streaming calculations into a series of short batch jobs. This paper expounds the architecture and programming model of spark streaming, and analyzes its core technology with practice,
Build a spark cluster entirely from 0Note: This step, only suitable for the use of root to build, formal environment should have permission classes of things behind another experiment to write tutorials1, install each software, set environment variables (each software needs to download separately)Export java_home=/usr/java/jdk1.8.0_71Export Java_bin=/usr/java/jdk1.8.0_71/binExport path= $JAVA _home/bin: $PATHExport classpath=.: $JAVA _home/lib/dt.jar:
In the conf file of your spark path, the CP copy Spark-defaults.conf.template is spark-defaults.conf
and add the following file
spark.eventLog.enabled trueSpark.eventLog.dir hdfs://master:9000/historySpark.eventLog.compress true
Distribute configuration to other child nodes I'm using rsync.
rsync sparkconf Path/spark
First, the foregoing
Spark resource Scheduling is a very important module, as long as the understanding of the principle, can specifically understand how spark is implemented, so particularly important.
In the case of voluntary application, this paper is divided into coarse grained and fine-grained models respectively.
second, the specific Spark Resource scheduli
1. Official website Download source code, address: http://spark.apache.org/downloads.html2. Use MAVEN to compile:Note Before you translate, you need to set the Java heap size and the permanent generation size to avoid MVN memory overflow.Under Windows Settings:%maven_home%\bin\mvn.cmd, place one of theAdd a row below this line of commentsSet maven_opts=-xmx2048m-xx:permsize=512m-xx:maxpermsize=1024mTo compile laterPackageWhen the compilation is complete, import the project into IntelliJFile->imp
Below is a look at the use of Union:Use the collect operation to see the results of the execution:Then look at the use of Groupbykey:Execution Result:The join operation is the process of a Cartesian product operation, as shown in the following example:To perform a join operation on RDD3 and RDD4:Use collect to view execution results:It can be seen that the join operation is exactly a Cartesian product operation;The reduce itself, which is an action-type operation in an RDD operation, causes the
the manager.For hash Based Shuffle, see Org.apache.spark.shuffle.FileShuffleBlockManager; for sort Based Shuffle, Please see Org.apache.spark.shuffle.IndexShuffleBlockManager.1.1.4 Org.apache.spark.shuffle.ShuffleReaderShufflereader implements the logic of how the downstream task reads the shuffle output of the upstream shufflemaptask. This logic is more complex, In simple terms, you get the location information of the data through Org.apache.spark.MapOutputTracker, and then if the data is loca
Run the example one by one to see the results illustrate Hadoop_home environment variablesOrg.apache.spark.examples.sql.hive.JavaSparkHiveExampleModify the run Configuration to add env hadoop_home=${hadoop_home}Run the Java class. After the hive example is exhausted, delete the metastore_db directory.Here's a simple way to run it one by oneEclipse->file->import->run/debug Launch ConfigurationBrowse to the Easy_dev_labs\runconfig directory. Import all.Now from Eclipse->run->run ConfigurationStart
1 installing spark-dependent Scala
1.2 Configure environment variables for Scala
1.3 validation Scala
2 Download and decompression spark
3 Spark-related configuration
3.1 Configuring environment variables
3.2 Configure the files in the Conf directory
3.2.1 New Spark-env.h file
3.2.2 New Slaves file
4 test st
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.