Mobility

Runtime MechanismThe overall structure of spout/bolt in a topology won’t be discussed in detail here. The focus is on the potential differences between Storm/JStorm topology runtime and traditional Java programs. In fact, there are very few differences, mainly体现在 initialization. The purpose of this article is to help developers troubleshoot potential topology program issues without needing to understand Storm’s internal principles. A topology contains multiple spout threads and bolt...

ActiveMQ’s web console is built on Jetty, and its permission management is also based on Jetty. Based on requirements, different permissions can be assigned to different users. Jetty’s permission management is fairly flexible, though it can be a bit cumbersome to configure. You can specify whether a particular role (role) has access to a specific page. Below is a brief introduction to the configuration method. You only need to modify the following files under /conf: jetty.xml and jetty-realm....

Storm UI is very helpful for troubleshooting issues encountered during Storm usage, but some properties have unclear meanings. Although they are all simple concepts, not knowing them can be quite frustrating. One thing to note: when you hover over the title bar in the UI, you can see the specific details of that property. Several highly-ranked Google articles are essentially just organizing this information. Most properties are straightforward — you know what they mean just by seeing the name...

Recently, while using ActiveMQ’s connection pool, I discovered a very serious memory leak issue. Through jmap monitoring, it can be seen that java.util.concurrent.locks.ReentrantLock and org.apache.activemq.pool.PooledConnection occupy a very large amount of memory, and the growth rate is also very fast. After searching online, I found exactly the corresponding ActiveMQ bug report: https://issues.apache.org/jira/browse/AMQ-3997 This bug has been fixed in version 5.7, so it can be resolved by ...

The company uses ActiveMQ and Camel for message distribution. Previously, the data volume wasn’t very large, so we never really considered efficiency issues, and the research into Camel’s working principles wasn’t deep. However, recently, as the business volume increased, Camel’s efficiency has gradually become a bottleneck, so I got a general understanding of Camel’s working principles based on logs. Although Camel is embedded into ActiveMQ, during the working process, Camel and ActiveMQ are...

Reposted from http://leyew.blog.51cto.com/5043877/860255#559183-tsina-1-46862-ed0973a0c870156ed15f06a6573c8bf0 A few days ago I started learning LDA, took many detours, and was still completely confused about LDA. After reading this document, I finally understood what LDA is for.   LDA (Latent Dirichlet Allocation) Learning NotesI’ve been studying the LDA algorithm recently, and after a few days of struggle, I’ve finally gained a rough understanding of the overall framework and process o...

Reference: http://www.cnblogs.com/xia520pi/archive/2012/05/16/2504205.html   123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137package org.apache.hadoop.examples;import java.io.IOException;import java.util.StringTokenizer;import org.apache...

http://www.cnblogs.com/xia520pi/archive/2012/05/16/2504205.html WordCount execution process detailed explanation http://www.cnblogs.com/gpcuster/archive/2010/06/04/1751538.html HDFS command introduction http://hi.baidu.com/gkf8605/item/d6b8af09c3463512eafe38b1 HDFS commands http://www.cnblogs.com/forfuture1978/archive/2010/11/14/1877086.html MapReduce introduction   http://hadoop.apache.org/docs/r0.20.2/api/index.html Hadoop 0.20.2 APISource: https://lichuanyang....