the implementation of join. And this operation plays a crucial role in the secondary sort mode. Secondary sort mode refers to the user expects data to be grouped by key and wants to traverse value in a specific order. UserepartitionandsortwithinpartitionsPlus a part of the user's extra work can achieve secondary sort.ConclusionYou should now have a good understanding of all the essential elements needed to complete an efficient Spark program. In part
unstable in earlier versions of Spark, and Spark does not want to break version compatibility, so Kryoserializer is not configured as the default, but Kryoserializer Should be the first choice under any circumstances.The frequency with which your record is switched in these two forms has a significant impact on the operational efficiency of the Spark application
ObjectiveIn the field of big data computing, Spark has become one of the increasingly popular and increasingly popular computing platforms. Spark's capabilities include offline batch processing in big data, SQL class processing, streaming/real-time computing, machine learning, graph computing, and many different types of computing operations, with a wide range of applications and prospects. In the mass reviews, many students have tried to use
Spark is especially suitable for multiple operations on specific data, such as mem-only and MEM disk. Mem-only: high efficiency, but high memory usage, high cost; mem Disk: After the memory is used up, it will automatically migrate to the disk, solving the problem of insufficient memory, it brings about the consumption of Data replacement. Common spark tuning w
level of most tasks has been boosted; see if the uptime of the entire spark job is shortenedBut be careful not to get the cart before the horse, the localization level is improved, but because of a lot of waiting time, the spark operation time increases, it is still not adjusted.Spark.locality.wait, default is 3s; can be changed to 6s,10sBy default, the following 3 wait lengths are the same as the one abov
Tuning OverviewMost spark job performance is mainly consumed in the shuffle link, because this link contains a lot of disk IO, serialization, network data transmission and other operations. Therefore, if you want to make the performance of the job to a higher level, it is necessary to tune the shuffle process. But it's
Tuning OverviewMost spark job performance is mainly consumed in the shuffle link, because this link contains a lot of disk IO, serialization, network data transmission and other operations. Therefore, if you want to make the performance of the job to a higher level, it is necessary to tune the shuffle process. But it's
to 10% of the memory size of each executor; and then we usually project, when we actually handle big data,
There will be problems here, causing the spark job to crash repeatedly and not run, and then adjust this parameter to at least 1G (1024M),
Even say 2G, 4G
Usually this parameter is adjusted up, will avoid some JVM oom abnormal problem, at the same time, will let the whole spark job
Original link: Spark Streaming performance tuning The Spark streaming provides an efficient and convenient streaming mode, but in some scenarios the default configuration is not optimal, and even the external data cannot be processed in real time, and we need to make relevant modifications to the default configuration.
In Spark, the most basic principle is that each task processes a partition of an RDD.
1, the advantages of mappartitions operation:If it is a normal map, such as 10,000 data in a partition, OK, then your function will be executed and calculated 10,000 times.However, after using the mappartitions operation, a task will only execute once function,function receive all partition data at once. As long as it executes once, the
1 read the Apache configuration optimization recommendations below, then adjust the relevant parameters to observe the status of the server.2 Apache Configuration Tuning Recommendations:3Enter/usr/local/apache2/conf/under the extra directory4 Apache optimization,5 after the above operation,
set-up value. The goal is to mitigate the effects of excessive procedures and therefore not buildDisable these settings globally. There is one more thing to note about Max_execution_time: It represents the CPU time of the process, not the absolute time. So a progressiveA program that runs large amounts of I/O and a small number of computations may run far more than Max_execution_time. This is also max_input_time can be greater thanThe reason for Max_execution_time.The number of log records that
value of the number of client-side request connections is maximum 20000 MaxClients 150# allow the number of client side request connections The default maxclients and Serverlimit must be increased by Maxclients Threadsperchild 25# Each child process establishes the number of threads to be executed by default 100~500 maximum value 20000 and threadlimit must be increased at the same time Threadlimit 200# Maximum number of threads per child process configurable Threadlimit>=threadsperchild Maxr
Apache Spark Memory Management detailedAs a memory-based distributed computing engine, Spark's memory management module plays a very important role in the whole system. Understanding the fundamentals of spark memory management helps to better develop spark applications and perform
Spark Applications-peilong Li 8. Avoid Cartesian operation
The Rdd.cartesian operation is time-consuming, especially when the dataset is large, the order of magnitude of the Cartesian is square-level, both time-consuming and space consuming.
>>> Rdd = Sc.parallelize ([1, 2])
>>> sorted (Rdd.cartesian (RDD). Collect ())
[(1, 1), (1, 2), (2 , 1), (2, 2)]
9. Avoid shuffle when possible
The shuffle in spark
As a memory-based distributed computing engine, Spark's memory management module plays a very important role in the whole system. Understanding the fundamentals of spark memory management helps to better develop spark applications and perform performance tuning. The purpose of this paper is to comb out the thread of
Original address: http://blog.cloudera.com/blog/2015/03/how-to-tune-your-apache-spark-jobs-part-2/
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In the conclusion to this series, learn how resource tuning, parallelism, and data representation affect Spark job perform Ance.
In this post, we'll finish what we started in "How to Tune Your
Resource parameter tuningOnce you understand the fundamentals of the spark job run, the parameters related to the resource are easy to understand. The so-called Spark resource parameter tuning, in fact, is the spark in the process of running the various resources used in the place, by adjusting various parameters to op
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