THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Example 3 - materialized view rebuild
needs: HIVE-22809
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-- some settings...they might be there already set hive.support.concurrency=true; set hive.txn.manager=org.apache.hadoop.hive.ql.lockmgr.DbTxnManager; set hive.strict.checks.cartesian.product=false; set hive.stats.fetch.column.stats=true; set hive.materializedview.rewriting=true; -- create some tables CREATE TABLE emps ( empid INT, deptno INT, name VARCHAR(256), salary FLOAT, hire_date TIMESTAMP) STORED AS ORC TBLPROPERTIES ('transactional'='true'); CREATE TABLE depts ( deptno INT, deptname VARCHAR(256), locationid INT) STORED AS ORC TBLPROPERTIES ('transactional'='true'); -- load data insert into emps values (100, 10, 'Bill', 10000, 1000), (200, 20, 'Eric', 8000, 500), (150, 10, 'Sebastian', 7000, null), (110, 10, 'Theodore', 10000, 250), (120, 10, 'Bill', 10000, 250), (1330, 10, 'Bill', 10000, '2020-01-02'); insert into depts values (10, 'Sales', 10), (30, 'Marketing', null), (20, 'HR', 20); insert into emps values (1330, 10, 'Bill', 10000, '2020-01-02'); -- create mv CREATE MATERIALIZED VIEW mv1 AS SELECT empid, deptname, hire_date FROM emps JOIN depts ON (emps.deptno = depts.deptno) WHERE hire_date >= '2016-01-01 00:00:00'; EXPLAIN SELECT empid, deptname FROM emps JOIN depts ON (emps.deptno = depts.deptno) WHERE hire_date >= '2018-01-01'; -- create a schedule to rebuild mv create scheduled query d cron '0 */10 * * * ? *' defined as alter materialized view mv1 rebuild; -- from this expalin it will be seen that the mv1 is being used EXPLAIN SELECT empid, deptname FROM emps JOIN depts ON (emps.deptno = depts.deptno) WHERE hire_date >= '2018-01-01'; -- insert a new record insert into emps values (1330, 10, 'Bill', 10000, '2020-01-02'); -- the source tables are scanned EXPLAIN SELECT empid, deptname FROM emps JOIN depts ON (emps.deptno = depts.deptno) WHERE hire_date >= '2018-01-01'; -- wait 10 minutes -- run it again...the view should be rebuilt EXPLAIN SELECT empid, deptname FROM emps JOIN depts ON (emps.deptno = depts.deptno) WHERE hire_date >= '2018-01-01'; |
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