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Contents of this issue:
Spark Streaming data cleansing principles and phenomena
Spark Streaming data Cleanup code parsing
The Spark streaming is always running, and the RDD is constantly generated during the calc
, Jobgenerator is used to generate jobs for each batch, it has a timer, and the timer's cycle is the StreamingContext set when the batchduration is initialized. As soon as this cycle is over, Jobgenerator will invoke the Generatejobs method to generate and submit jobs, after which the Docheckpoint method is invoked to checkpoint. The Docheckpoint method determines whether the difference between the current time and the streaming application start is a
sparkstreaming framework wants to run the spark engineer to write the business logic processing code * * * * Javastrea
Mingcontext JSC = new Javastreamingcontext (SC, durations.seconds (6)); * * Third step: Create spark streaming enter data source input Stream: * 1, data input source can be based on file, HDFS, Flume, Kafk
First, the Java Way development1, pre-development preparation: Assume that you set up the spark cluster.2, the development environment uses Eclipse MAVEN project, need to add spark streaming dependency.3. Spark streaming is calcul
1. Background overview
There is a certain demand in the business, in the hope of real-time to the data from the middleware in the already existing dimension table inner join, for the subsequent statistics. The dimension table is huge, with nearly 30 million records, about 3g data, and the cluster's resources are strained, so you want to squeeze the performance and throughput of spark streaming as much as po
Many distributed computing systems can handle big data streams in real-time or near real-time. This article will briefly introduce the three Apache frameworks, and then try to quickly and highly outline their similarities and differences. Apache Stormin Storm, we first design a graph structure for real-time computing, which we call topology (topology). This topology will be presented to the cluster, which distributes the code by the master node in the cluster and assigns the task to the worker n
Spark Streaming 1.2 provides a Wal based fault-tolerant mechanism (refer to the previous blog post http://blog.csdn.net/yangbutao/article/details/44975627), You can guarantee that the calculation of the data is executed at least once,
However, it is not guaranteed to perform only once, for example, after Kafka receiver write data to Wal, to zookeeper write offse
includes Spark, Mesos, Akka, Cassandra, and Kafka, with the following features:
Contains lightweight toolkits that are widely used in big data processing scenarios
Powerful community support with open source software that is well-tested and widely used
Ensures scalability and data backup at low latency.
A unified cluster management platform to manage diverse, different load application
. We must find a good balance between the two parameters, because we do not want the data block to be too large, and do not want to wait too long for localization. We want all tasks to be completed within several seconds.
?? Therefore, we changed the localization options from 3 s to 1 s, and we also changed the block interval to 1.5 s.
--conf "spark.locality.wait=1s" --conf "spark.streaming.blockInterval=1500ms" \2.6 merge temporary files
?? Inext4In the file system, we recommend that you enable
Schema background spark parameter optimization increase Executor-cores resize executor-memory num-executors set first deal decompression policy x Message Queuing bug bypass PHP end limit processing Action 1 processing speed increased from 1 to 10 peak Period non-peak status description increased from 10 to 50 peak off-peak status description use pipeline to elevate the QPS of the Redis 50 to a full-scale PM period Peak State Analysis
Architecture
back
Follow the spark and Kafka tutorials step-by-step, and when you run the Kafkawordcount example, there is always no expected output. If it's right, it's probably like this:
......
-------------------------------------------
time:1488156500000 Ms
------------------------------------- ------
(4,5) (
8,12)
(6,14)
(0,19)
(2,11)
(7,20)
(5,10)
(9,9)
(3,9
) (1,11)
...
In fact, only:
......
----------------------
1. Join for different time slice data streams
After the first experience, I looked at Spark WebUi's log and found that because spark streaming needed to run every second to calculate the data in real time, the program had to read HDFs every second to get the data for the inner join.
Sparkstreaming would have cached the data it was processing to reduce IO and incr
In order to better understand the processing mechanism of the spark streaming sub-framework, you have to figure out the most basic concepts yourself.1. Discrete stream (discretized stream,dstream): This is the spark streaming's abstract description of the internal continuous real-time data stream, a real-time data stream We're working on, in
) The exception here is because the Kafka is reading the specified offset log (here is 264245135 to 264251742), because the log is too large, causing the total size of the log to exceed Fetch.message.max.bytesThe Set value (default is 1024*1024), which causes this error. The workaround is to increase the value of fetch.message.max.bytes in the parameters of the Kafka client.For example://
Analysis of Spark Streaming principlesReceive Execution Process Data
StreamingContextDuring instantiation, You need to inputSparkContextAnd then specifyspark matser urlTo connectspark engineTo obtain executor.
After instantiation, you must first specify a method for receiving data, as shown in figure
val lines = ssc.socketTextStream(localhost, 9999)
In this way, text data is received from the socket. In thi
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