hive - How PARTITIONED BY works? -


i have created below table, want understand how partition works, partition column logdate not part of table ddl how partition works , how data distribution & retrieval happens.

create table tbl_1 ( collecttimestamp timestamp, objectcolumnname varchar(256), objectdatabasename           varchar(256), typeofuse                    tinyint ) partitioned (logdate string) row format delimited fields terminated '\u0001' stored orc location '/tables/db1/tbl_1' ;

the partition column ``definitely part of table ddl, because partitioned by ddl. partition folder, it's not necessary store partition key data in data files. partition information (partition key, location) stored in metastore database. partition column should last in insert overwrite sentence dynamic partition load. when query table, hive reads information partitions (keys, locations) metastore. location (folder) can attached partition:

alter table page_view add partition (dt='2008-08-08', country='us') location '/path/to/us/part080808'

see docs here: https://cwiki.apache.org/confluence/display/hive/languagemanual+ddl


Comments

Post a Comment

Popular posts from this blog

php - Vagrant up error - Uncaught Reflection Exception: Class DOMDocument does not exist -

i've set bento/ubuntu-16.04 vagrant box using php 5.6, , getting following error quite few times when try , run shell script: "uncaught reflection exception: class domdocument not exist". i've tried adding following top of script (not together), each no success: "sudo apt-get install php5.6-xml", "sudo apt-get install php5-xml", "sudo apt-get install php-dom" i've tried resetting server "sudo service apache2 restart". does have suggestions?
Read more

vue.js - Create hooks for automated testing -

Image
qa guys complained can't automate frontend testing. because our html looks same outside. lazy hack did this <template> <div :role="$options.name"> ... </div> </template> <script> export default { name: 'vmcomponentname' } </script> which takes name script , applies html. in browser get: <div role="vmcomponentname"> ... </div> line :role="$options.name" goes in every component. is there dry er solutions? please share. additional details i'll explain in details looking for. imagine have vmusercreate form creates user. test case can create user . to automatically test without role, have use following selector: .wrapper > .wrapper > .wrapper > .submit-button the test extremely brittle (will break lot). if use roles can use [role="vmusercreateform"] .submit-button selector. many folds less brittle. so basically, i'm ...
Read more

Add new key value to json node in java -

i have json file : { "id":1, "name":"abc", "addressdetails": { "city":"newyork" } } i wanted add 1 more key-value ("pincode" : "414141") node 'addressdetails'. i tried using : objectmapper mapper = new objectmapper(); jsonnode root = mapper.readtree(new file("d://test.json")); objectnode node = mapper.createobjectnode(); node.with("addressdetails").put("pincode", "414141"); but it's not getting added, there way can ? you can try you should modify file path objectmapper mapper = new objectmapper(); objectnode nodes = mapper.readvalue(new file("d:\\test.txt"), objectnode.class); nodes.with("addressdetails").put("pincode", "414141"); mapper.writer().writevalue(new file("d:\\test.txt"), nodes);
Read more