使用sqoop从mysql往hive中增量导数据shell脚本

浏览数：244 / 时间：2015年06月12日

一：sqoop增量导入的两种方式

Incremental import arguments:

Argument	Description
`--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