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Cloud computing: Redefining IT over the past year, cloud computing exploded, including a variety of applications-such as Salesforce CRM and Google apps-and services-such as hosting Amazon elastic Compute Cloud (Amaz On EC2) ibm®db2®, Google ...

Java Iterator is an interface that provides only the basic rules for iteration, and a foreach loop can be used for any container that implements the Iterable interface.

Intermediary transaction http://www.aliyun.com/zixun/aggregation/6858.html ">seo diagnose Taobao guest cloud host technology Hall in the Web development, some systems require the same user at the same time to log on only once, 　　That is, if a user has logged in, if you log in before exiting, you need to error. The common approach is to determine whether the user is already in the creator when the user logs in, ...

Intermediary transaction http://www.aliyun.com/zixun/aggregation/6858.html ">seo diagnose Taobao guest Cloud host technology Hall willing to network support 10 million pv/database caching system is mainly built in hibernate Above the efficient database caching system, which contains a distributed solution, the system has been used to be willing to online, did not find a big problem, I also believe that the system is strong enough to cope with millions of ...

After completing the four basic learning steps of Apache Cassandra, you can try the actual code. If necessary, it is recommended to briefly review: Apache Cassandra Learning Step (1) Apache Cassandra Learning Ste ...

1. HQueue profile HQueue is a set of distributed, persistent message queues developed by hbase based on the search web crawl offline Systems team. It uses htable to store message data, HBase coprocessor to store the original keyvalue data in the message data format, and encapsulates the HBase client API for message access based on the HQueue client API. HQueue can be effectively used in the need to store time series data, as MAPR ...

1, metadata (Metadata): Maintenance of HDFs file System file and directory information, divided into memory metadata and metadata file two kinds. Namenode maintains the entire metadata. HDFs implementation, the method of periodically exporting metadata is not adopted, but the backup mechanism of metadata mirroring file (fsimage) + day file (edits) is adopted. 2, Block: The contents of the file. Search path Flow: &http://www.aliyun.com/zixun/aggregation/37 ...

1, namenode Start load metadata scenario analysis Namenode function call Fsnamesystemm read dfs.http://www.aliyun.com/zixun/aggregation/11696.html "> Namenode.name.dir and Dfs.namenode.edits.dir build Fsdirectory. Fsimage class Recovertransitionread and ...

This article describes the use of java iterators to traverse ArrayList collections, Set collections, and Map collections.

This article is my second time reading Hadoop 0.20.2 notes, encountered many problems in the reading process, and ultimately through a variety of ways to solve most of the. 　　Hadoop the whole system is well designed, the source code is worth learning distributed students read, will be all notes one by one post, hope to facilitate reading Hadoop source code, less detours. 1 serialization core Technology The objectwritable in 0.20.2 version Hadoop supports the following types of data format serialization: Data type examples say ...