hive 动态加载数据到指定分区，以及其他hive使用的技巧

hive修改分隔符：

1. alter table tableName set SERDEPROPERTIES('field.delim'='\t'); 
   

hive根据数据创建分区，并且动态加载数据到分区

1. insert into table device_status_log partition(  date ) 

   select `vin`,`obd_id` , `function_id` , `message_id` ,`message_content` ,
   `longitude`,`latitude` ,`speed` ,`engine_speed` ,`gps_stat`,`client_time`,
   `create_time`,`analytical_result`,regexp_replace( to_date(create_time ) ,'-','') as date 
   from pre_device_status_log ;

如果报如下错误的话

Dynamic partition strict mode requires at least one static partition column. To turn this off set hive.exec.dynamic.partition.mode=nonstrict

按照提示在hivecCli设置 ：set hive.exec.dynamic.partition.mode=nonstrict

Loading data to table obd_message.device_status_log partition (date=null)
         Time taken for load dynamic partitions : 4073
        Loading partition {date=20161020}
        Loading partition {date=20161017}
        Loading partition {date=20161024}
        Loading partition {date=20161021}
        Loading partition {date=20161023}
        Loading partition {date=20161026}
        Loading partition {date=20161015}
        Loading partition {date=20161018}
        Loading partition {date=20161016}
        Loading partition {date=20161019}
        Loading partition {date=20161025}
        Loading partition {date=20161022}
         Time taken for adding to write entity : 6
Partition obd_message.device_status_log{date=20161015} stats: [numFiles=1, numRows=188, totalSize=79565, rawDataSize=79377]
Partition obd_message.device_status_log{date=20161016} stats: [numFiles=1, numRows=648, totalSize=299298, rawDataSize=298650]
Partition obd_message.device_status_log{date=20161017} stats: [numFiles=1, numRows=912, totalSize=414597, rawDataSize=413685]
Partition obd_message.device_status_log{date=20161018} stats: [numFiles=1, numRows=895, totalSize=410935, rawDataSize=410040]
Partition obd_message.device_status_log{date=20161019} stats: [numFiles=1, numRows=1412, totalSize=613903, rawDataSize=612491]
Partition obd_message.device_status_log{date=20161020} stats: [numFiles=1, numRows=475, totalSize=204375, rawDataSize=203900]
Partition obd_message.device_status_log{date=20161021} stats: [numFiles=1, numRows=346, totalSize=142079, rawDataSize=141733]
Partition obd_message.device_status_log{date=20161022} stats: [numFiles=1, numRows=561, totalSize=220711, rawDataSize=220150]
Partition obd_message.device_status_log{date=20161023} stats: [numFiles=1, numRows=856, totalSize=352452, rawDataSize=351596]
Partition obd_message.device_status_log{date=20161024} stats: [numFiles=1, numRows=1997, totalSize=783701, rawDataSize=781704]
Partition obd_message.device_status_log{date=20161025} stats: [numFiles=1, numRows=1384, totalSize=556970, rawDataSize=555586]
Partition obd_message.device_status_log{date=20161026} stats: [numFiles=1, numRows=326, totalSize=133275, rawDataSize=132949]

hive查看分区

1. show partitions  device_status_log ;

hive正则匹配去除指定分隔符：

create_time 类型为2016-10-10 00:00:00

1. regexp_replace( to_date(create_time ) ,'-','') as date 
   
   

hive 时间函数 添加分钟或者秒

1. from_unixtime(unix_timestamp(client_time) + 8*3600 ) as client_time 
   

hive 自带的时间 函数 有date_add(   ) 但是只能对天进行增加减少

1. date        date(       date_add(   date_sub(   datediff(   datetime    
   

有些tips

创建hiveInit.sh

编辑内容如下 （此处的目的是为了能够尽量让job在本地执行，缩短等待时间，方便调试）：

SET mapred.job.tracker=local;
set mapred.reduce.tasks = 1;
set hive.exec.mode.local.auto.input.files.max=1000;
set hive.exec.mode.local.auto.inputbytes.max=50000000;
set hive.exec.mode.local.auto.tasks.max=10;
set hive.exec.mode.local.auto=true; 
set hive.cli.print.current.db=true;
set hive.cli.print.header=true;
show databases;
use obd_message;

在编辑 hiveStart.sh

hive -i hiveInit.sh

然后修改执行权限 在当前目录执行 ./hiveStart.sh  就能以指定的配置启动hiveClient