h base introduction & development
DESCRIPTION
HBase Development JavaTRANSCRIPT
HBASE INTRODUCTION & DEVELOPMENT
The term planet-size web application comes to mind, and in this case it is fitting
WHAT IS IT?
• It is the Hadoop database,
• Sclable
• Distributed
• BigDatastore
• Column Oriented
HBASE
HDFS
Reader Writer
FEATURES OF HBASE
• Scalable.
• Automatic failover
•Consistent reads and writes.
• Sharding of tables
• Failover support
•Classes for backing Hadoop map reduce jobs
• Java API for client access
• Thrift gateway and a REST Web
• Shell support
WHAT IT IS NOT
•No-Sql
•No relation
•No joins
•Not a replacement of RDBMS
• NoSQL
• HBase is a type of "NoSQL" database. "NoSQL" is a general term meaning that the database isn't an RDBMS which supports SQL as its primary access language.
• When we should think of using it
• HBase isn't suitable for every problem. We should have lot of data, if data is less RDBMS is better.
• Difference Between HDFS and HBase
• HDFS is a distributed file system that is well suited for the storage of large files. It's documentation states that it is not, however, a general purpose file system, and does not provide fast individual record lookups in files. HBase, on the other hand, is built on top of HDFS and provides fast record lookups (and updates) for large tables.
THINK ON THIS
• Facebook, for example, is adding more than 15 TB, and processing daily
• Google adding Peta-Bytes of data and processing.
• Companies storing Logs, temperature details, and many other prospective to store and process, which come in Peta-byte for which conventional technologies will days to read the data forget about processing it.
WHAT IS COLUMNS ORIENTED MEANS
• Grouped by columns,
• The reason to store values on a per-column basis instead is based on the assumption
• that, for specific queries, not all of the values are needed.
• Reduced I/O
COMPONENTS
HMASTER
• Master server is responsible for monitoring all RegionServer instances in the cluster, and is the interface for all metadata changes, it runs on the server which hosts namenode.
• Master controls critical functions such as RegionServer failover and completing region splits. So while the cluster can still run for a time without the Master, the Master should be restarted as soon as possible.
ZOOKEEPER
• Zookeeper is an open source software providing a highly reliable, distributed coordination service
• Entry point for an HBase system
• It includes tracking of region servers, where the root region is hosted
API
• Interface to HBase
• Using these we can we can access HBase and perform read/write and other operation on HBase.
• REST, Thrift, and Avro
• Thrift API framework, for scalable cross-language services development, combines a software stack with a code generation engine to build services that work efficiently and seamlessly between C++, Java, Python, PHP, Ruby, Erlang, Perl, Haskell, C#, Cocoa, JavaScript, Node.js, Smalltalk, OCaml and Delphi and other languages.
• lib
• commons-configuration-1.8.jar
• commons-lang-2.6.jar
• commons-logging-1.1.1.jar
• hadoop-core-1.0.0.jar
• hbase-0.92.1.jar
• log4j-1.2.16.jar
• slf4j-api-1.5.8.jar
• slf4j-log4j12-1.5.8.jar
• zookeeper-3.4.3.jar
Header Files you need to import
• import org.apache.hadoop.conf.Configuration;
• import org.apache.hadoop.hbase.HBaseConfiguration;
• import org.apache.hadoop.hbase.HColumnDescriptor;
• import org.apache.hadoop.hbase.HTableDescriptor;
• import org.apache.hadoop.hbase.KeyValue;
• import org.apache.hadoop.hbase.MasterNotRunningException;
• import org.apache.hadoop.hbase.ZooKeeperConnectionException;
• import org.apache.hadoop.hbase.client.Delete;
• import org.apache.hadoop.hbase.client.Get;
• import org.apache.hadoop.hbase.client.HBaseAdmin;
• import org.apache.hadoop.hbase.client.HTable;
• import org.apache.hadoop.hbase.client.Result;
• import org.apache.hadoop.hbase.client.ResultScanner;
• import org.apache.hadoop.hbase.client.Scan;
• import org.apache.hadoop.hbase.client.Put;
• import org.apache.hadoop.hbase.util.Bytes;
Header Files you need to import
• Configuration hConf = HBaseConfiguration.create(conf); hConf.set(Constants.HBASE_CONFIGURATION_ZOOKEEPER_QUORUM, hbaseZookeeperQuorum); hConf.set(Constants.HBASE_CONFIGURATION_ZOOKEEPER_CLIENTPORT, hbaseZookeeperClientPort); HTable hTable = new HTable(hConf, tableName);
• public class HBaseTest {
• private static Configuration conf = null;
• /**
• * Initialization
• */
• static {
• conf = HBaseConfiguration.create();
• }
• }
• /** Create a table
• */
• public static void creatTable(String tableName, String[] familys)
• throws Exception { HBaseAdmin admin = new HBaseAdmin(conf);
• if (admin.tableExists(tableName)) {System.out.println("table already exists!");
• } else { HTableDescriptor tableDesc = new HTableDescriptor(tableName);
• for (int i = 0; i < familys.length; i++) {
• tableDesc.addFamily(new HColumnDescriptor(familys[i]));
• }admin.createTable(tableDesc);
• System.out.println("create table " + tableName + " ok.");
• }
• }
•
• /** * Delete a table
• */
• public static void deleteTable(String tableName) throws Exception {
• try {HBaseAdmin admin = new HBaseAdmin(conf);
• admin.disableTable(tableName);
• admin.deleteTable(tableName);
• System.out.println("delete table " + tableName + " ok.");
• } catch (MasterNotRunningException e) {
• e.printStackTrace();
• } catch (ZooKeeperConnectionException e) {
• e.printStackTrace();
• }
• }
• /**
• * Put (or insert) a row
• */
• public static void addRecord(String tableName, String rowKey,String family, String qualifier, String value) throws Exception {
• try {HTable table = new HTable(conf, tableName);
• Put put = new Put(Bytes.toBytes(rowKey));
• put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier), Bytes
• .toBytes(value));
• table.put(put);
• System.out.println("insert recored " + rowKey + " to table "
• + tableName + " ok.");
• } catch (IOException e) {e.printStackTrace();
• }
• }
• /**
• * Delete a row
• */
• public static void delRecord(String tableName, String rowKey)
• throws IOException {HTable table = new HTable(conf, tableName);
• List<Delete> list = new ArrayList<Delete>();
• Delete del = new Delete(rowKey.getBytes());
• list.add(del);
• table.delete(list);
• System.out.println("del recored " + rowKey + " ok.");
• }
• /**Get a row
• */
• public static void getOneRecord (String tableName, String rowKey) throws IOException{
• HTable table = new HTable(conf, tableName);
• Get get = new Get(rowKey.getBytes());
• Result rs = table.get(get);
• for(KeyValue kv : rs.raw()){
• System.out.print(new String(kv.getRow()) + " " );
• System.out.print(new String(kv.getFamily()) + ":" );
• System.out.print(new String(kv.getQualifier()) + " " );
• System.out.print(kv.getTimestamp() + " " );
• System.out.println(new String(kv.getValue()));
• }
• }
• /** Scan (or list) a table */
• public static void getAllRecord (String tableName) {
• try{
• HTable table = new HTable(conf, tableName);
• Scan s = new Scan();
• ResultScanner ss = table.getScanner(s);
• for(Result r:ss){
• for(KeyValue kv : r.raw()){
• System.out.print(new String(kv.getRow()) + " ");
• System.out.print(new String(kv.getFamily()) + ":"); System.out.print(new String(kv.getQualifier()) + " ");
• System.out.print(kv.getTimestamp() + " "); System.out.println(new String(kv.getValue())); } }
• } catch (IOException e){
• e.printStackTrace();
• }
• }
• public static void main(String[] agrs) {
• try {
• String tablename = "scores";
• String[] familys = { "grade", "course" };
• HBaseTest.creatTable(tablename, familys);
• // add record zkb
• HBaseTest.addRecord(tablename, "zkb", "grade", "", "5");
• HBaseTest.addRecord(tablename, "zkb", "course", "", "90");
• HBaseTest.addRecord(tablename, "zkb", "course", "math", "97");
• HBaseTest.addRecord(tablename, "zkb", "course", "art", "87");
• // add record baoniu
• HBaseTest.addRecord(tablename, "baoniu", "grade", "", "4");
• HBaseTest.addRecord(tablename, "baoniu", "course", "math", "89");
•
•
• System.out.println("===========get one record========");
• HBaseTest.getOneRecord(tablename, "zkb");
• System.out.println("===========show all record========");
• HBaseTest.getAllRecord(tablename);
• System.out.println("===========del one record========");
• HBaseTest.delRecord(tablename, "baoniu");
• HBaseTest.getAllRecord(tablename);
• System.out.println("===========show all record========");
• HBaseTest.getAllRecord(tablename);
• } catch (Exception e) {
• e.printStackTrace();
• }
• }}
