Extract hive table partition in Spark - java

Question

Is there any way in Spark to extract only partition column names? The workaround I am using is to run \"show extended table like table_name\" using HiveContex

Answer 1

You can use class HiveMetaStoreClient to query directly from HiveMetaStore.

This class is widely used by popular APIS also, for interacting with HiveMetaStore for ex: Apache Drill

org.apache.hadoop.hive.metastore.api.Partition getPartition(String db_name, String tbl_name, List part_vals)

org.apache.hadoop.hive.metastore.api.Partition getPartition(String db, String tableName, String partName) Map> getPartitionColumnStatistics(String dbName, String tableName, List partNames, List colNames)

Get partitions column statistics given dbName, tableName, multiple partitions and colName-s

List getPartitionsByNames(String db_name, String tbl_name, List part_names) Get partitions by a list of partition names.

Also, there are list methods as well..

List listPartitionNames(String db_name, String tbl_name, List part_vals, short max_parts)

List listPartitionNames(String dbName, String tblName, short max)

List listPartitions(String db_name, String tbl_name, List part_vals, short max_parts)

List listPartitions(String db_name, String tbl_name, short max_parts)

Sample Code snippet 1 :

import org.apache.hadoop.hive.conf.HiveConf;

// test program
public class Test {
    public static void main(String[] args){

        HiveConf hiveConf = new HiveConf();
        hiveConf.setIntVar(HiveConf.ConfVars.METASTORETHRIFTCONNECTIONRETRIES, 3);
        hiveConf.setVar(HiveConf.ConfVars.METASTOREURIS, "thrift://host:port");

        HiveMetaStoreConnector hiveMetaStoreConnector = new HiveMetaStoreConnector(hiveConf);
        if(hiveMetaStoreConnector != null){
            System.out.print(hiveMetaStoreConnector.getAllPartitionInfo("tablename"));
        }
    }
}


// define a class like this

import com.google.common.base.Joiner;
import com.google.common.collect.Lists;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.HiveMetaStoreClient;
import org.apache.hadoop.hive.metastore.api.FieldSchema;
import org.apache.hadoop.hive.metastore.api.MetaException;
import org.apache.hadoop.hive.metastore.api.Partition;
import org.apache.hadoop.hive.metastore.api.hive_metastoreConstants;
import org.apache.hadoop.hive.ql.metadata.Hive;
import org.apache.thrift.TException;
import org.joda.time.DateTime;
import org.joda.time.format.DateTimeFormatter;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class HiveMetaStoreConnector {
    private HiveConf hiveConf;
    HiveMetaStoreClient hiveMetaStoreClient;

    public HiveMetaStoreConnector(String msAddr, String msPort){
        try {
            hiveConf = new HiveConf();
            hiveConf.setVar(HiveConf.ConfVars.METASTOREURIS, msAddr+":"+ msPort);
            hiveMetaStoreClient = new HiveMetaStoreClient(hiveConf);
        } catch (MetaException e) {
            e.printStackTrace();
            System.err.println("Constructor error");
            System.err.println(e.toString());
            System.exit(-100);
        }
    }

    public HiveMetaStoreConnector(HiveConf hiveConf){
        try {
            this.hiveConf = hiveConf;
            hiveMetaStoreClient = new HiveMetaStoreClient(hiveConf);
        } catch (MetaException e) {
            e.printStackTrace();
            System.err.println("Constructor error");
            System.err.println(e.toString());
            System.exit(-100);
        }
    }

    public String getAllPartitionInfo(String dbName){
        List<String> res = Lists.newArrayList();
        try {
            List<String> tableList = hiveMetaStoreClient.getAllTables(dbName);
            for(String tableName:tableList){
                res.addAll(getTablePartitionInformation(dbName,tableName));
            }
        } catch (MetaException e) {
            e.printStackTrace();
            System.out.println("getAllTableStatistic error");
            System.out.println(e.toString());
            System.exit(-100);
        }

        return Joiner.on("\n").join(res);
    }

    public List<String> getTablePartitionInformation(String dbName, String tableName){
        List<String> partitionsInfo = Lists.newArrayList();
        try {
            List<String> partitionNames = hiveMetaStoreClient.listPartitionNames(dbName,tableName, (short) 10000);
            List<Partition> partitions = hiveMetaStoreClient.listPartitions(dbName,tableName, (short) 10000);
            for(Partition partition:partitions){
                StringBuffer sb = new StringBuffer();
                sb.append(tableName);
                sb.append("\t");
                List<String> partitionValues = partition.getValues();
                if(partitionValues.size()<4){
                    int size = partitionValues.size();
                    for(int j=0; j<4-size;j++){
                        partitionValues.add("null");
                    }
                }
                sb.append(Joiner.on("\t").join(partitionValues));
                sb.append("\t");
                DateTime createDate = new DateTime((long)partition.getCreateTime()*1000);
                sb.append(createDate.toString("yyyy-MM-dd HH:mm:ss"));
                partitionsInfo.add(sb.toString());
            }

        } catch (TException e) {
            e.printStackTrace();
            return Arrays.asList(new String[]{"error for request on" + tableName});
        }

        return partitionsInfo;
    }

    public String getAllTableStatistic(String dbName){
        List<String> res = Lists.newArrayList();
        try {
            List<String> tableList = hiveMetaStoreClient.getAllTables(dbName);
            for(String tableName:tableList){
                res.addAll(getTableColumnsInformation(dbName,tableName));
            }
        } catch (MetaException e) {
            e.printStackTrace();
            System.out.println("getAllTableStatistic error");
            System.out.println(e.toString());
            System.exit(-100);
        }

        return Joiner.on("\n").join(res);
    }

    public List<String> getTableColumnsInformation(String dbName, String tableName){
        try {
            List<FieldSchema> fields = hiveMetaStoreClient.getFields(dbName, tableName);
            List<String> infs = Lists.newArrayList();
            int cnt = 0;
            for(FieldSchema fs : fields){
                StringBuffer sb = new StringBuffer();
                sb.append(tableName);
                sb.append("\t");
                sb.append(cnt);
                sb.append("\t");
                cnt++;
                sb.append(fs.getName());
                sb.append("\t");
                sb.append(fs.getType());
                sb.append("\t");
                sb.append(fs.getComment());
                infs.add(sb.toString());
            }

            return infs;

        } catch (TException e) {
            e.printStackTrace();
            System.out.println("getTableColumnsInformation error");
            System.out.println(e.toString());
            System.exit(-100);
            return null;
        }
    }
}

Sample code snippet example 2 (source)

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.HiveMetaStoreClient;
import org.apache.hadoop.hive.metastore.api.Database;
import org.apache.hadoop.hive.metastore.api.MetaException;
import org.apache.hadoop.hive.metastore.api.NoSuchObjectException;
import org.apache.hive.hcatalog.common.HCatUtil;
import org.apache.thrift.TException;

import javax.xml.crypto.Data;
import java.io.IOException;
import java.util.HashMap;

public class HiveMetaStoreClientTest {
    public static void main(String[] args) {

        HiveConf hiveConf = null;
        HiveMetaStoreClient hiveMetaStoreClient = null;
        String dbName = null;

        try {
            hiveConf = HCatUtil.getHiveConf(new Configuration());
            hiveMetaStoreClient = new HiveMetaStoreClient(hiveConf);

            dbName = args[0];

            getDatabase(hiveMetaStoreClient, dbName);


        } catch (MetaException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (NoSuchObjectException e) {
            e.printStackTrace();
            System.out.println("===============");
            System.out.println("database " + args[0] + "not exists");
            System.out.println("===============");
            createDatabase(hiveMetaStoreClient, dbName);
            try {
                getDatabase(hiveMetaStoreClient, dbName);
            } catch (TException e1) {
                e1.printStackTrace();
                System.out.println("TMD");
            }
        } catch (TException e) {
            e.printStackTrace();
        }
    }

    public static Database getDatabase(HiveMetaStoreClient hiveMetaStoreClient, String dbName) throws TException {
        Database database = null;

        database = hiveMetaStoreClient.getDatabase(dbName);

        System.out.println(database.getLocationUri());
        System.out.println(database.getOwnerName());

        for (String key : database.getParameters().keySet()) {
            System.out.println(key + " = " + database.getParameters().get(key));
        }
        return database;
    }

    public static Database createDatabase(HiveMetaStoreClient hiveMetaStoreClient, String dbName) {
        HashMap<String, String> map = new HashMap<String,String>();
        Database database = new Database(dbName, "desc", null, map);
        try {
            hiveMetaStoreClient.createDatabase(database);
        } catch (TException e) {
            e.printStackTrace();
            System.out.println("some error");
        }
        return database;
    }
}