一:sqoop增量导入的两种方式

Incremental import arguments:

ArgumentDescription
--check-column (col) Specifies the column to be examined when determining which rows to import. (the column should not be of type CHAR/NCHAR/VARCHAR/VARNCHAR/ LONGVARCHAR/LONGNVARCHAR)
--incremental (mode) Specifies how Sqoop determines which rows are new. Legal values for mode include append and lastmodified.
--last-value (value) Specifies the maximum value of the check column from the previous import.

此处采用的--increamental append方式,这种方式需注意主键或split-colunm是递增,否则建议在关系表中增加一个createTime字段,采用lastmodified方式。

 

二:shell脚本

    

 1 #!/bin/sh
 2 export SQOOP_HOME=/usr/share/sqoop-1.4.4
 3 hostname="192.168.1.199"
 4 user="root"
 5 password="root"
 6 database="test"
 7 table="tags"
 8 curr_max=0
 9 
10 function db_to_hive(){
11 
12     ${SQOOP_HOME}/bin/sqoop import --connect jdbc:mysql://${hostname}/${database} --username ${user} --password ${password}  --table ${table}   --split-by docid --hive-import --hive-table lan.ding  
13  --fields-terminated-by '\t' --incremental  append  --check-column docid --last-value ${curr_max}   
14     result=`mysql -h${hostname} -u${user} -p${password} ${database}<<EOF 
15 select max(docid) from ${table};
16 EOF`
17 curr_max=`echo $result |awk '{print $2}'`
18 }
19 
20 if [ $# -eq 0 ];then
21     while true
22     do
23       db_to_hive
24       sleep 120
25     done
26     exit
27 fi

每隔2分钟,就往hive中增量导入数据。

posted on 2014-06-20 17:59  LIUSANNITY  阅读(2016)  评论(2编辑  收藏  举报