hadoop syntax

and create an indexed field DSHive> CREATE TABLE invites (foo INT, bar string) partitioned by (DS string);1.8 Copying an empty tableCREATE TABLE Empty_key_value_storeLike Key_value_store;ExampleCreate Table User_info (user_idintby'\ t'by '\ n';ExampleThe data format for importing data tables is: The fields are tab-divided, and lines are broken.and to our file content format:100636 100890 C5c86f4cddc15eb7 YYYVYBTVT100612 100865 97cc70d411c18b6f Gyvcycy100078 100087 Ecd6026a15ffddf5 qa0001001.9

Tags: style io color ar using SP data on ArtA colleague summarizes the hive SQL optimizations Hive is a tool that generates a string resolution that conforms to SQL syntax to generate mapreduce that can be executed on Hadoop. Using hive to design SQL as many of the features of distributed computing as possible differs from traditional relational databases, So we need to get rid of the original relational da

• Insert query results into hive table• Write query results to the HDFs file system• Basic ModeINSERT OVERWRITE TABLE tablename1 [PARTITION (Partcol1=val1, Partcol2=val2 ...)] Select_statement1 from From_stat Ement• Multi-insert modeFrom from_statementINSERT OVERWRITE TABLE tablename1 [PARTITION (Partcol1=val1, Partcol2=val2 ...)] Select_statement1[INSERT OVERWRITE TABLE tablename2 [PARTITION ...] select_statement2] ...• Auto Partition modeINSERT OVERWRITE TABLE tablename PARTITION (Partcol1[=va

] partition_spec [location ' Location1 '] partition_spec [location ' Location2 '] ...Partition_spec:: PARTITION (Partition_col = partition_col_value, Partition_col = Partiton_col_value, ...)Delete partition: ALTER TABLE table_name DROP partition_spec, Partition_spec,...Iv. changing table file format and organizationALTER TABLE table_name SET fileformat File_formatALTER TABLE table_name CLUSTERED by (userid) SORTED by (viewtime) to num_buckets bucketsThis command modifies the physical storage pro

;Build Bucket TableCREATE TABLE par_table (viewtime INT, UserID BIGINT, Page_url string, referrer_url string, IP string COMMENT ' IP Address of the User ') COMMENT ' the Page view table ' partitioned by (date STRING, pos string) CLUSTERED by (userid ) SORTED by (Viewtime) to BUCKETS ROW FORMAT delimited ' \ t ' fields TERMINATED by ' \ n ' STORED as sequencefile; Create a table and create an indexed field DSHive> CREATE TABLE invites (foo INT, bar string) partitioned by (DS string); Copy an emp

filter in the WHERE clause--or write in the join clause• Easy to confuse problem is the case of table partitioningSelect C.val, d.val from C left OUTER JOIN D on (C.key=d.key)WHERE a.ds= ' 2010-07-07 ' and b.ds= ' 2010-07-07 '• If no record of the corresponding C table is found in the D table, all columns in the D table are listed as NULL, including the DS column. That is, join filters all records in the D table that match the C table join key cannot be found. In this case, the left OUTER cause

I. Job input and output optimizationUse Muti-insert, union All, the union all of the different tables equals multiple inputs, union all of the same table, quite map outputExample　　Second, data tailoring2.1. Column ClippingWhen hive reads the data, it can query only the columns that are needed, ignoring the other columns. You can even use an expression that is being expressed.See. Http://www.cnblogs.com/bjlhx/p/6946202.html2.2. Partition clippingReduce unnecessary partitioning during queryExample

Tags: table operations CLU SQL ROM Tilt sort complete Section Select sortFirst, the data to re-order 1.1, go to Heavy Distinct and GROUP by Try to avoid using distinct for weight, especially large table operations, using GROUP by instead -- Not recommended Select DISTINCT Key from a -- Recommended Select Key from Group by Key 1.2. Sorting optimization Only order by produces a globally ordered result, which can be sorted according to the actual scenario. 1, order by to achieve global ordering

map phase through the script/bin/CAT (like hadoop streaming). Similarly-streaming can be used on the reduce side (please see the hive tutorial or examples)Actual ExampleCreate a tableCreate Table u_data (Userid int,Movieid int,Rating int,Unixtime string)Row format delimitedFields terminated by '/t'Stored as textfile;Download the sample data file and decompress it.Wget http://www.grouplens.org/system/files/ml-data.tar__0.gzTar xvzf ml-data.tar__0.gzLo

Install times wrong: Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.7:run (site) on project Hadoop-hdfs:an Ant B Uildexception has occured:input file/usr/local/hadoop-2.6.0-stable/hadoop-2.6.0-src/hadoop-hdfs-project/ Hadoop-hdfs/target/findbugsxml.xml

Hadoop Foundation----Hadoop Combat (vi)-----HADOOP management Tools---Cloudera Manager---CDH introduction We have already learned about CDH in the last article, we will install CDH5.8 for the following study. CDH5.8 is now a relatively new version of Hadoop with more than hadoop2.0, and it already contains a number of

Chapter 2 mapreduce IntroductionAn ideal part size is usually the size of an HDFS block. The execution node of the map task and the storage node of the input data are the same node, and the hadoop performance is optimal (Data Locality optimization, avoid data transmission over the network ). Mapreduce Process summary: reads a row of data from a file, map function processing, Return key-value pairs; the system sorts the map results. If there are multi

1. Hadoop Java APIThe main programming language for Hadoop is Java, so the Java API is the most basic external programming interface.2. Hadoop streaming1. OverviewIt is a toolkit designed to facilitate the writing of MapReduce programs for non-Java users.Hadoop streaming is a programming tool provided by Hadoop that al

-asl.jar" verbose = "true" /> Modify the jar File Cd./hadoop-1.2.1/src/contrib/eclipse-plugin/META-INF vi MANIFEST.MF Find the Bundle-ClassPath line of the file and modify it Bundle-ClassPath: classes/, lib/commons-cli.jar, lib/commons-httpclient.jar, lib/hadoop-core.jar, lib/jackson-mapper-asl.jar, lib/commons-configuration.jar, lib/commons-lang.jar, lib/jackson-core-asl.jar Ensure that the preceding cha

Directory structure Hadoop cluster (CDH4) practice (0) PrefaceHadoop cluster (CDH4) Practice (1) Hadoop (HDFS) buildHadoop cluster (CDH4) Practice (2) Hbasezookeeper buildHadoop cluster (CDH4) Practice (3) Hive BuildHadoop cluster (CHD4) Practice (4) Oozie build Hadoop cluster (CDH4) practice (0) Preface During my time as a beginner of

dfsadmin-reportAppearLive Datanodes (2):This information indicates that the cluster was established successfullyAfter successful startup, you can access the Web interface http://192.168.1.151:50070 View NameNode and Datanode information, and you can view the files in HDFS online.Start YARN to see how tasks work through the Web interface: Http://192.168.1.151:8088/cluster command to manipulate HDFsHadoop FSThis command lists all the help interfaces for the sub-commands of HDFs. Basically the

Wang Jialin's in-depth case-driven practice of cloud computing distributed Big Data hadoop in July 6-7 in Shanghai Wang Jialin Lecture 4HadoopGraphic and text training course: Build a true practiceHadoopDistributed Cluster EnvironmentHadoopThe specific solution steps are as follows: Step 1: QueryHadoopTo see the cause of the error; Step 2: Stop the cluster; Step 3: Solve the Problem Based on the reasons indicated in the log. We need to clear th

[Hadoop] how to install Hadoop and install hadoop Hadoop is a distributed system infrastructure that allows users to develop distributed programs without understanding the details of the distributed underlying layer. Important core of Hadoop: HDFS and MapReduce. HDFS is res

This document describes how to operate a hadoop file system through experiments. Complete release directory of "cloud computing distributed Big Data hadoop hands-on" Cloud computing distributed Big Data practical technology hadoop exchange group:312494188Cloud computing practices will be released in the group every day. welcome to join us! First, let's loo

Not much to say, directly on the dry goods!GuideInstall Hadoop under winEveryone, do not underestimate win under the installation of Big data components and use played Dubbo and disconf friends, all know that in win under the installation of zookeeper is often the Disconf learning series of the entire network the most detailed latest stable disconf deployment (based on Windows7 /8/10) (detailed) Disconf Learning series of the full network of the lates