Update table (Acid)

 Update table in Hive by using ACID properties

Prerequisites :-

(1) Table should be Bucketized.
(2) ORC format
(3) Need to set 2 properties:
     (a) SET hive.txn.manager=org.apache.hadoop.hive.ql.lockmgr.DbTxnManager;
     (b) SET hive.support.concurrency=true;

Step: 1 => Create table using TBLPROPERTIES('transactional'=true');


create table testacid(id int, name string, rollno int) clustered by (id) into 4 buckets
stored as ORC tblproperties('transactional'='true') ;


Step : 2 =>  Insert records into table.

insert into testacid values(1,'dh1',121),(2,'dh2',122);

Step : 3 =>  update testacid set name='dheeren' where name='dh2';

Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

Error :   Caused by: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient

Solution: This issue is related with Metastore which will done by help of database e,g Derby, MySql etc...

First steps 

Verify hive-site.xml with below properties.

 <name>javax.jdo.option.ConnectionURL</name>

    <value>jdbc:derby:;databaseName=metastore_db;create=true</value>

   

<name>javax.jdo.option.ConnectionDriverName</name>

    <value>org.apache.derby.jdbc.EmbeddedDriver</value>

    

  <name>hive.metastore.warehouse.dir</name>

    <value>hdfs://localhost:9000/user/hive/warehouse</value>

 <property>

    <name>hive.metastore.uris</name>

    Keep it BLANK

Now try again to start HIVE.If you are still getting the same problem.

Please follow below steps:

(1) Remove metastore_db directory if exists

     rm -r metastore_db

(2) Now initiate Schema by command schematool from hive bin directory 

       schematool -initSchema -dbType derby

(3)     IF Schematool complete successfully the please start hive.

         Now you can able to use database in hive.