org.apache.hadoop.hive.ql.parse.repl.dump.HiveWrapper Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.hive.ql.parse.repl.dump;
import org.apache.hadoop.hive.metastore.api.Database;
import org.apache.hadoop.hive.ql.metadata.Hive;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.metadata.Table;
import org.apache.hadoop.hive.ql.parse.ReplicationSpec;
/**
* The idea for this class is that since we need to make sure that
* we query the replication id from the db before we do any queries
* to get the object from metastore like tables/functions/partitions etc
* we are devising this wrapper to wrap all such ordering of statements here.
*/
public class HiveWrapper {
private final Hive db;
private final String dbName;
private final Tuple.Function functionForSpec;
public HiveWrapper(Hive db, String dbName) {
this(db, dbName, 0);
}
public HiveWrapper(Hive db, String dbName, long lastReplId) {
this.dbName = dbName;
this.db = db;
this.functionForSpec = new BootStrapReplicationSpecFunction(db, lastReplId);
}
public Tuple function(final String name)
throws HiveException {
return new Tuple<>(functionForSpec, () -> db.getFunction(dbName, name));
}
public Tuple database() throws HiveException {
return new Tuple<>(functionForSpec, () -> db.getDatabase(dbName));
}
public Tuple table(final String tableName) throws HiveException {
return new Tuple<>(functionForSpec, () -> db.getTable(dbName, tableName));
}
public static class Tuple {
interface Function {
T fromMetaStore() throws HiveException;
}
public final ReplicationSpec replicationSpec;
public final T object;
/**
* we have to get the replicationspec before we query for the function object
* from the hive metastore as the spec creation captures the latest event id for replication
* and we dont want to miss any events hence we are ok replaying some events as part of
* incremental load to achieve a consistent state of the warehouse.
*/
Tuple(Function replicationSpecFunction,
Function functionForObject) throws HiveException {
this.replicationSpec = replicationSpecFunction.fromMetaStore();
this.object = functionForObject.fromMetaStore();
}
}
}
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