1.查看目录下面有多少文件数
ls -l |grep "^-"|wc -l
思路很明显了,ls后通过grep进行过滤判断是文件还是文件夹,
如果是判断文件夹,可以使用ls -l |grep "^d"|wc -l
2.copy命令连接数据库 并分批导入文件到数据库中
下面是我的示例代码,可以分批把数据导入到数据库中.同时捕获错误的信息与错误的记录.
date
totalcount=1315890897;
onetimecount=100000000;
for (( c=1100000001; c<$totalcount; c=c+$onetimecount))
do
date;
sdate=`date +%y%m%d%H%M%S`
echo "$c rows";
cat /CLQR/Factory/FlowTest/Cimation/outbound/201401/part-r-00000 | tail -n+$c | head -$onetimecount |/opt/vertica/bin/vsql -h yourhostname -d yourdbname -U accountname -w your!password -c "copy clqr_az.STG_INKJET_TEST_DATA201401 from local stdin direct no escape null as 'N' DELIMITER E' 02' REJECTED DATA '201401_excpata_$sdate.txt' exceptions '201401$sdate.err' ";
date;
done;
使用copy的时候,需要注意的两点是,如果你的列分隔符 有问题,譬如说有些列内部有列分隔符 本身,这样就会造成找到的列比表本身多,会有问题.
如果你的行分隔符有问题,默认是 ,就会找到的列比设计的列少,都会被拒绝载入的.
我们可以加上exception选项和rejected data选项捕获这些错误的信息与错误的数据,以方便查找原因.
我的项目中出现过类似的问题,我的解决方案是使用不可见字符譬如 01与 02分别做列与列的分隔符 .
注意:如果你的密码中含有特殊字符,譬如说!之类的,是需要进行转义的 加上
3.
vertica优化代码
--optimize
select dbd_create_workspace('Test')
select dbd_create_design('Test','Test');
select dbd_add_design_tables('Test','clqr_az.STG_INKJET_TEST_DATA');
select dbd_populate_design('Test','Test');
--Execute
select dbd_create_deployment('Test', 'Test');
select dbd_add_deployment_design('Test', 'Test', 'Test');
select dbd_add_deployment_drop('Test', 'Test');
select dbd_execute_deployment('Test', 'Test');
--Cleanup
select dbd_drop_deployment('Test', 'Test');
select dbd_remove_design('Test', 'Test');
select dbd_drop_design('Test', 'Test');
select dbd_drop_workspace('Test');
当然你也可以手动去启动database desinger.然后针对特定的query设计projections.
4.
给表重命名的步骤:
Alter table schemaname.tablename rename to newtablenamewithoutschema ;
select analyze_statistics ('schema.tablename');
select refresh ('schema.tablename');
这样也会保持projection的数据up to date.
5.如何查看被删除的数据
可以使用at epoch 或 at timestamp 'sometime'之类的查询.
可以在select语句之前加上 at epoch latest来读取当前时间的记录,类似于sqlserver中的snapshot.
这样不阻塞其他进程写数据.
在 Merge ,INSERT 后面加入/*direct*/,可以防止WOS full之类的错误,大数据时直接写入ROS.
有时候表join会把内存爆掉,可以加入: /*+set_vertica_options(EE, ENABLE_JOIN_SPILL)*/
允许其外部排序.
6.创建projections
一开始我们并不太熟悉如何创建合适的projections,推荐使用database desinger自动生成,然后学习这个生成的规则,我使用的感觉就是非常像使用sqlserver或其他关系数据库系统中的覆盖索引(视图).
但是它往往需要你创建一个buddy projections.
下面是一个示例:
CREATE PROJECTION TableName_DBD_2_seg_evan_dbd_b0 /*+basename(TableName_DBD_2_seg_evan_dbd),createtype(D)*/ ( Test_Step_Fact_Key ENCODING DELTARANGE_COMP, Serial_Number ENCODING AUTO, Test_Run_Number ENCODING COMMONDELTA_COMP, Project_Name ENCODING RLE, Sequence_Name ENCODING RLE, Step_Start_Local_Timestamp ENCODING COMMONDELTA_COMP, Step_Start_UTC_Timestamp ENCODING COMMONDELTA_COMP, Step_Start_Local_Day_Dimension_Key ENCODING COMMONDELTA_COMP, Step_Number ENCODING BLOCKDICT_COMP, Manufacturer_Site_Key ENCODING RLE ) AS SELECT Test_Step_Fact_Key, Serial_Number, Test_Run_Number, Project_Name, Sequence_Name, Step_Start_Local_Timestamp, Step_Start_UTC_Timestamp, Step_Start_Local_Day_Dimension_Key, Step_Number, Manufacturer_Site_Key FROM TableName ORDER BY Manufacturer_Site_Key, Project_Name, Sequence_Name, Serial_Number SEGMENTED BY MODULARHASH (Serial_Number, Project_Name, Sequence_Name, Manufacturer_Site_Key) ALL NODES OFFSET 0; CREATE PROJECTION TableName_DBD_2_seg_evan_dbd_b1 /*+basename(TableName_DBD_2_seg_evan_dbd),createtype(D)*/ ( Test_Step_Fact_Key ENCODING DELTARANGE_COMP, Serial_Number ENCODING AUTO, Test_Run_Number ENCODING COMMONDELTA_COMP, Project_Name ENCODING RLE, Sequence_Name ENCODING RLE, Step_Start_Local_Timestamp ENCODING COMMONDELTA_COMP, Step_Start_UTC_Timestamp ENCODING COMMONDELTA_COMP, Step_Start_Local_Day_Dimension_Key ENCODING COMMONDELTA_COMP, Step_Number ENCODING BLOCKDICT_COMP, Manufacturer_Site_Key ENCODING RLE ) AS SELECT Test_Step_Fact_Key, Serial_Number, Test_Run_Number, Project_Name, Sequence_Name, Step_Start_Local_Timestamp, Step_Start_UTC_Timestamp, Step_Start_Local_Day_Dimension_Key, Step_Number, Manufacturer_Site_Key FROM TableName ORDER BY Manufacturer_Site_Key, Project_Name, Sequence_Name, Serial_Number SEGMENTED BY MODULARHASH (Serial_Number, Project_Name, Sequence_Name, Manufacturer_Site_Key) ALL NODES OFFSET 1; View Code