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@sasaki 2016-03-07T09:24:36.000000Z 字数 7374 阅读 2603

Hive——数据仓库

BigData

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  1. @Title          Hive——数据仓库
  2. @Version        v1.0
  3. @Timestamp      2016-02-19 16:34
  4. @Author         Nicholas
  5. @Mail           redskirt@outlook.com

Hadoop最基本的两大模块：分布式存储和分布式计算。

QQ截图20160219163923.jpg-132.9kB

Hive Metastore

内部表指hive创建并通过load data inpath进数据库的表，这种表可以理解为数据和表结构都保存在一起的数据表。当你通过DROP TABLE table_name 删除元数据中表结构的同时，表中的数据也同样会从hdfs中被删除。

外部表指在表结构创建以前，数据已经保存在hdfs中了，通过创建表结构，将数据格式化到表的结构里。当DROP TABLE table_name 的时候，hive仅仅会删除元数据的表结构，而不会删除hdfs上的文件，所以，相比内部表，外部表可以更放心大胆的使用。

  1. [root@master tmp]# hive
  2. 16/02/19 16:49:48 WARN conf.HiveConf: DEPRECATED: Configuration property hive.metastore.local no longer has any effect. Make sure to provide a valid value for hive.metastore.uris if you are connecting to a remote metastore.
  4. Logging initialized using configuration in jar:file:/opt/cloudera/parcels/CDH-5.3.8-1.cdh5.3.8.p0.5/jars/hive-common-0.13.1-cdh5.3.8.jar!/hive-log4j.properties
  5. hive> show databases;
  6. OK
  7. default
  8. Time taken: 0.806 seconds, Fetched: 1 row(s)
  9. hive> show tables;
  10. OK
  11. Time taken: 0.083 seconds
  12. hive> create table test (a int, b string);
  13. OK
  14. Time taken: 0.304 seconds
  16. # 分别建立存储外部表和内部表的目录
  17. [root@master tmp]# hadoop fs -mkdir /user/root/hive/external
  18. [root@master tmp]# hadoop fs -mkdir /user/root/hive/internal
  20. [root@master tmp]# hadoop fs -put SogouQ.reduced /user/root/hive/external
  21. [root@master tmp]# hadoop fs -put SogouQ.reduced /user/root/hive/internal
  23. # 创建外部表
  24. hive> create external table log_in(time varchar(8), userid varchar(30), query string, pagerank int, clickrank int, site string) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' location 'hdfs://192.168.53.230:8020/user/root/hive/external';
  25. OK
  26. Time taken: 0.096 seconds
  27. hive> select * from log_in limit 10;
  28. OK
  29. 00:00:00    2982199073774412    [360安全卫士]   8   3   download.it.com.cn/softweb/software/firewall/antivirus/20067/17938.html
  30. 00:00:00    07594220010824798   [哄抢救灾物资]    1   1   news.21cn.com/social/daqian/2008/05/29/4777194_1.shtml
  31. 00:00:00    5228056822071097    [75810部队]   14  5   www.greatoo.com/greatoo_cn/list.asp?link_id=276&title=%BE%DE%C2%D6%D0%C2%CE%C5
  32. 00:00:00    6140463203615646    [绳艺]    62  36  www.jd-cd.com/jd_opus/xx/200607/706.html
  33. 00:00:00    8561366108033201    [汶川地震原因]    3   2   www.big38.net/
  34. 00:00:00    23908140386148713   [莫衷一是的意思]   1   2   www.chinabaike.com/article/81/82/110/2007/2007020724490.html
  35. 00:00:00    1797943298449139    [星梦缘全集在线观看] 8   5   www.6wei.net/dianshiju/????\xa1\xe9|????do=index
  36. 00:00:00    00717725924582846   [闪字吧]   1   2   www.shanziba.com/
  37. 00:00:00    41416219018952116   [霍震霆与朱玲玲照片] 2   6   bbs.gouzai.cn/thread-698736.html
  38. 00:00:00    9975666857142764    [电脑创业]  2   2   ks.cn.yahoo.com/question/1307120203719.html
  39. Time taken: 0.083 seconds, Fetched: 10 row(s)

Partitions

  1. hive> CREATE TABLE log_partitions(time varchar(8), userid varchar(30), query string, pagerank int, clickrank int, site string) PARTITIONED BY (day STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';
  2. OK
  3. Time taken: 0.826 seconds
  5. [root@master ~]# hadoop fs -cp /user/root/hive/external/SogouQ.reduced /user/root/hive/partitions
  7. hive> LOAD DATA INPATH '/user/root/hive/partitions' INTO TABLE log_partitions PARTITION(day='2014-01-01');
  8. Loading data to table default.log_partitions partition (day=2014-01-01)
  9. chgrp: changing ownership of 'hdfs://master:8020/user/hive/warehouse/log_partitions/day=2014-01-01/SogouQ.reduced': User does not belong to hive
  10. Partition default.log_partitions{day=2014-01-01} stats: [numFiles=1, numRows=0, totalSize=160939045, rawDataSize=0]
  11. OK
  12. Time taken: 1.044 seconds
  14. # 建表时未指定目录，该表将默认放到/user/hive/warehouse中
  15. [root@master ~]# hadoop fs -ls /user/hive/warehouse
  16. Found 2 items
  17. drwxrwxrwt   - root hive          0 2016-02-24 11:02 /user/hive/warehouse/log_partitions
  18. drwxrwxrwt   - root hive          0 2016-02-19 16:51 /user/hive/warehouse/test
  19. # 指定的partitions条件被创建为目录
  20. [root@master ~]# hadoop fs -ls /user/hive/warehouse/log_partitions
  21. Found 1 items
  22. drwxrwxrwt   - root hive          0 2016-02-24 11:02 /user/hive/warehouse/log_partitions/day=2014-01-01
  23. [root@master ~]# hadoop fs -ls -R /user/hive/warehouse/log_partitions
  24. drwxrwxrwt   - root hive          0 2016-02-24 11:02 /user/hive/warehouse/log_partitions/day=2014-01-01
  25. -rwxrwxrwt   3 root root  160939045 2016-02-24 11:01 /user/hive/warehouse/log_partitions/day=2014-01-01/SogouQ.reduced
  27. # 查询时可带上分区条件查询
  28. hive> select * from log_partitions where day='2014-01-01' limit 10;
  29. OK
  30. 00:00:00    2982199073774412    [360安全卫士]   8   3   download.it.com.cn/softweb/software/firewall/antivirus/20067/17938.htm2014-01-01
  31. 00:00:00    07594220010824798   [哄抢救灾物资]    1   1   news.21cn.com/social/daqian/2008/05/29/4777194_1.shtml  2014-01-01
  32. 00:00:00    5228056822071097    [75810部队]   14  5   www.greatoo.com/greatoo_cn/list.asp?link_id=276&title=%BE%DE%C2%D6%D0%C2%CE%C5  2014-01-01
  33. 00:00:00    6140463203615646    [绳艺]    62  36  www.jd-cd.com/jd_opus/xx/200607/706.html    2014-01-01
  34. 00:00:00    8561366108033201    [汶川地震原因]    3   2   www.big38.net/  2014-01-01
  35. 00:00:00    23908140386148713   [莫衷一是的意思]   1   2   www.chinabaike.com/article/81/82/110/2007/2007020724490.html  2014-01-01
  36. 00:00:00    1797943298449139    [星梦缘全集在线观看] 8   5   www.6wei.net/dianshiju/????\xa1\xe9|????do=index    2014-01-01
  37. 00:00:00    00717725924582846   [闪字吧]   1   2   www.shanziba.com/   2014-01-01
  38. 00:00:00    41416219018952116   [霍震霆与朱玲玲照片] 2   6   bbs.gouzai.cn/thread-698736.html    2014-01-01
  39. 00:00:00    9975666857142764    [电脑创业]  2   2   ks.cn.yahoo.com/question/1307120203719.html 2014-01-01
  40. Time taken: 0.152 seconds, Fetched: 10 row(s)
  42. # 查看表结构，可看到有一个名为day的Partitions域
  43. hive> desc log_partitions;
  44. OK
  45. time                    varchar(8)                                  
  46. userid                  varchar(30)                                 
  47. query                   string                                      
  48. pagerank                int                                         
  49. clickrank               int                                         
  50. site                    string                                      
  51. day                     string                                      
  53. # Partition Information      
  54. # col_name              data_type               comment             
  56. day                     string                                      
  57. Time taken: 0.124 seconds, Fetched: 12 row(s)
  1. ../sogouqueryfish/day=2014-01-01/..
  2. ../sogouqueryfish/day=2014-01-02/..
  3. ..
  4. ../sogouqueryfish/day=2014-01-06/..

Bucket

假设，在user_id列上执行查询 ，在user_id列上使用buckets。

  1. CREATE TABLE page_views_old(user_id INT, session_id INT, url STRING)
  2. PARTITIONED BY(day INT) ROW FORMAT DELIMITED FIELDS TERMINATED BY ',';
  3. LOAD DATA INPATH '/data/PageView/pageview.sample' INTO TABLE
  4. page_views_old PARTITION(day=1);
  5. set hive.enforce.bucketing = true;
  6. CREATE TABLE page_views(user_id INT, session_id INT, url STRING) PARTITIONED
  7. BY(day INT) clustered by(user_id) into 10 buckets ROW FORMAT DELIMITED
  8. FIELDS TERMINATED BY ',';
  9. from page_views_old insert overwrite table page_views partition(day=1) select
  10. user_id,session_id,url where day=1;

通过以上语句，表中的数据将会根据user_id的哈希数分成10个buckets。因此，当查询确定的user_id时，程序首先计算user_id的哈希数然后只查找对应的bucket。

查询搜索次数最多的用户及其搜索的内容倒序排列，前10条记录
select sf.userid, sf.query, count(sf.query) sco, tt.co from (select userid, count(3) co from log_in group by userid order by co desc) as tt join log_in as sf on tt.userid = sf.userid group by sf.userid,sf.query,tt.co order by tt.co desc,sco desc limit 10;

Hive Beeline模式

  1. [root@slave01 ~]# beeline
  2. Beeline version 0.13.1-cdh5.3.8 by Apache Hive
  3. !connect jdbc:hive2://master:10000
  4. scan complete in 3ms
  5. Connecting to jdbc:hive2://master:10000
  6. Enter username for jdbc:hive2://master:10000: hive
  7. Enter password for jdbc:hive2://master:10000: ****
  8. Connected to: Apache Hive (version 0.13.1-cdh5.3.8)
  9. Driver: Hive JDBC (version 0.13.1-cdh5.3.8)
  10. Transaction isolation: TRANSACTION_REPEATABLE_READ
  11. 0: jdbc:hive2://master:10000>
  12. 0: jdbc:hive2://master:10000> show tables;
  13. +-----------------+--+
  14. |    tab_name     |
  15. +-----------------+--+
  16. | log_in          |
  17. | log_partitions  |
  18. | sogouquery      |
  19. | test            |
  20. +-----------------+--+
  21. 4 rows selected (0.823 seconds)

search-qeury项目

  2. [root@master tmp]# hadoop fs -mkdir /user/root/search-query
  4. hive> CREATE EXTERNAL TABLE search_query(time varchar(8), userid varchar(30), query string, pagerank int, clickrank int, site string) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' location 'hdfs://192.168.53.230:8020/user/root/search-query';
  5. OK
  6. Time taken: 0.07 seconds

http://www.68idc.cn/help/buildlang/ask/20150719452542.html

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