writable table

Writable computed observables writable computed monitoring propertiesThe requirements for writable monitoring properties are high and are not commonly used in most situations.In general, the computed monitoring property has a value calculated from other monitoring properties, and it is usually read-only and looks strange, but it is possible to make the computed m

Novice can ignore this section, writable dependency monitoring property is really too advanced, and most of the situation is not used.In general, the value of the calculated monitor is calculated from the values of other monitoring properties, so it is read-only. It seems strange that we have any way to make him writable. At this point, we just need to provide a callback function to do it.By using your cust

This article address: http://www.cnblogs.com/archimedes/p/hadoop-writable.html, reprint please indicate source address.Hadoop has a lot of writable classes in the Org.apache.hadoop.io package, in which the more important are Java basic classes, Text, writable collections, objectwritable, etc. The implementation of Java basic classes and objectwritable is highlighted.1. Java basic type of

Serialization principles from Hadoop Writable serialization framework to java After the previous module, the analysis content comes to the Hadoop IO-related module. The module of the IO system is a relatively large module, In the Hadoop Common io, it consists of two major sub-modules, one is a serialization Module Based on the Writable interface, and the other is a decompression module. Therefore, we plan t

stream and transmits it to another process over the network. Another process receives the byte stream and returns it to a structured object through deserialization, to achieve inter-process communication. In Hadoop, the serialization and deserialization technologies must be used for communication between Mapper, Combiner, and CER stages. For example, the intermediate result ( ) Needs to be written to the local hard disk. This is a serialization process (converting a structured object into a b

In Hadoop, there is no basic type class (Integer, float, etc.) that comes with Java, but instead uses the classes that you have developed. Hadoop comes with a number of serialization types, roughly divided into the following two categories: Classes that implement the Writablecomparable interface Base: booleanwritable | BytewritableNumbers: intwritable | vintwritable | floatwritable | longwritable | vlongwritable | DoublewritableAdvanced: nullwritable | Text | byteswritable | Mdshas

This article address: http://www.cnblogs.com/archimedes/p/hadoop-writable-interface.html, reprint please indicate source address.Introduction serialization and deserialization are transitions between structured objects and byte streams, primarily in the context of internal process communication and persistent storage.Communication Format RequirementsHadoop's internal communication between nodes uses the RPC,RPC protocol to translate the message into a

PHP is readable and not writable, how can I modify it? Number: The above is the background code, but only can read, can not be modified to submit to the database, how can I modify it so that he can modify the commit store to the database? Share to: 号码：号码： ------Solution-------------------- You are the HTML code, to write to the data will be in PHP to get your table of this line of content, and then

for clients in multiple languages Storage format requirements on the surface it seems that the serialization framework may need some other features in persistent storage, but in fact it is still the four points: 1. compression, less space occupied 2. fast, fast read/write 3. scalable. You can read old data in the old format. good compatibility. It supports reading and writing hadoop's serialization format in multiple languages. hadoop's own serialization storage format implements the

This blog is an original article, reproduced please indicate the source: http://guoyunsky.iteye.com/blogs/1265944 When I first came into contact with hadoop, sequencefile and writable had a bit of association and thought it was amazing. later, I learned that some I/O protocols are used for input and output. this section describes how to read and write writable data from Sequence File.

Take intwritable as an example to introduce the steps to customize the writable//the Writablecomparable interface inherits the writable interface and the comparable interface Public classIntwritableImplementsWritablecomparable {//define member variables for ordinary Java typesPrivate intvalue;//set method for member variables Public voidSetintValue) { This. Value =value;}//get methods for member variables P

I. Interpretation of file permissionsAs shown, the beginning of the-rwxrw-r--string identifies the file permissions.This string has 10 bits, which can be divided into 4 segments to interpret. Note: r--readable, w--writable, x--executable.The first paragraph (1th bit) indicates whether it is a directory or a file,-indicates a file, and D indicates a directory;The second paragraph (第2-4位, a total of 3 strings) represents the permissions that the file's

Today to help friends to maintain the server, in the shutdown Database command found MySQL closed, prompted warning:world-writable config file '/etc/my.cnf ' is ignored, probably means that the permissions of the global writable, any user can write. MySQL is concerned about this file being maliciously modified by other users, so ignore the configuration file. So MySQL can't shut down. Let's look at the who

Custom writable Hadoop has implemented some very useful writable, and you can do a lot of things with their combinations, but if you want to construct some more complex results, you can customize writable to achieve your goal, we annotate the way Explain the custom writable (not to mention that I only post the code fo

Tags: file www. User ID inf local who syntax work meaningChmod is the right to change a file Chown is the owner and genus of the modified file Chgrp only the genus group that changed the file.I. Interpretation of file permissionsAs shown, the beginning of the-rwxrw-r--string identifies the file permissions.This string has 10 bits, which can be divided into 4 segments to interpret. Note: r--readable, w--writable, x--executable.The first paragraph (1

There is a set of writable implementations in Hadoop that can meet most requirements, but in some cases we need to construct a new implementation based on our own needs, and with custom writable, we have complete control over binary representations and sort orders.To demonstrate how to create a custom writable type, we need to write an implementation that represe

the SetEnumerator method is not used. All sets do not have a writable iterator attribute. The original reasons for this roommate are as follows: 1. This violates the open and closed principles in the design model. Iterations set to the set may directly cause exceptions or changes to the set's behavior. Once a new iteration requirement is required, you can create a new iterator to meet the requirement, instead of setting the iterator for the set, this

in the persistence of storage, but in fact it remains the four points: 1. Compressed, less space occupied 2. Fast, can read and write quickly 3. Scalable, old data can be read in old format 4. Good compatibility, can support reading and writing in multiple languages Serialization format for Hadoop The serialized storage format for Hadoop itself is the class that implements the writable interface, and he only implements the first two points, com

Problem analysis In the Shutdown database command found that MySQL can not be closed, the hint Warning: World-writable config file '/etc/my.cnf' is ignored , probably means that the permissions of the global writable, any user could write. MySQL is concerned about this file being maliciously modified by other users, so ignore the configuration file. So MySQL can't shut down. Let's look at the whole proce

/*** To test the writable nature of the directory** @param string $dir* @return int 1 writable 0 not writable* Source DZ* Xiao Jia (www.phpcina.cn) organized in 2006-06-26*/function Dir_writeable ($dir) {/*** $dir if not the directory will create a readable and writable directory*/if (!is_dir ($dir)) {@mkdir ($dir, 077