HBase Connector

Overview

The HBase Connector allows querying and creating tables on an external Apache HBase instance. Users can create a table in HBase connector, mapping it to an existing table in HBase Cluster, and support insert, select, or delete.

The HBase Connector maintains a Metastore to persist HBase metadata, currently only following storage format are supported as Metastore: Local File System, Hadoop Distributed File System (HDFS), and openLooKeng Metastore.

Note: Apache HBase 1.3.1 version is supported by HBase connector

Connector Configuration

Create etc/catalog/hbase.properties to mount the HBase connector as the HBase catalog, replacing the hbase.xxx properties as required:

connector.name=hbase-connector
hbase.zookeeper.quorum=xxx.xxx.xxx.xxx,xxx.xxx.xxx.xxx
hbase.zookeeper.property.clientPort=xxxx
hbase.metastore.type=local
hbase.metastore.uri=/xxx/hbasemetastore.ini

For the value of hbase.zookeeper.quorum, please use comma (,) as the delimiter if it has multiple ip addresses.

Note

If you are using Local File System, HDFS as Metastore, you need to create an empty file , such as hbasemetastore.ini.

Use HDFS to store HBase metadata

You need to add below properties:

hbase.core.site.path=/xxx/core-site.xml
hbase.hdfs.site.path=/xxx/hdfs-site.xml
hbase.metastore.type=hdfs
hbase.metastore.uri=hdfs://xxx.xxx.xxx.xxx:21088/xxx/hbasemetastore.ini

Use openLooKeng Metastore to store HBase metadata

You have to create etc/hetu-metastore.properties to connect database. For the details of configuration, please refer to VDM Connector. Adding below property to the configuration file:

hbase.metastore.type=hetuMetastore

Kerberos Configuration:

hbase.jaas.conf.path=/xxx/jaas.conf
hbase.hbase.site.path=/xxx/hbase-site.xml
hbase.krb5.conf.path=/xxx/krb5.conf
hbase.kerberos.keytab=/xxx/user.keytab
hbase.kerberos.principal=xxx
hbase.authentication.type=KERBEROS

Configuration Properties

Table Properties

Data Types

Currently, following 10 data type are supported: VARCHAR, TINYINT, SMALLINT, INTEGER, BIGINT, DOUBLE, BOOLEAN, TIME, DATE and TIMESTAMP.

Push Down

The HBase Connector supports push down most of operators, such as rowkey-based point query, rowkey-based range query. Besides, those predicate conditions are supported to push down: =, >=, >, <, <=, !=, in, not in, is null, is not null, between and.

Usage Examples

The HBase Connector basically supports all SQL statements, includes creating, querying, and deleting schemas; Adding, dropping, and modifying tables; Inserting data, deleting rows and so on.

Here are some example:

Create Schema

CREATE SCHEMA schemaName;

Drop Schema

It can only drop empty schema.

DROP SCHEMA schemaName;

Create Table

HBase Connector supports two forms of table creation:

1. Create a table and directly link to a existing table in the HBase data source.

2. Create a new table that does not exist in the HBase data source.

Below is an example of how to create a table schemaName.tableName and link it to an existing table named hbaseNamespace:hbaseTable :

CREATE TABLE schemaName.tableName (
    rowId        VARCHAR,
    qualifier1    TINYINT,
    qualifier2    SMALLINT,
    qualifier3    INTEGER,
    qualifier4    BIGINT,
    qualifier5    DOUBLE,
    qualifier6    BOOLEAN,
    qualifier7    TIME,
    qualifier8    DATE,
    qualifier9    TIMESTAMP
)
WITH (
    column_mapping = 'rowId:f:rowId, qualifier1:f1:q1, qualifier2:f1:q2, 
    qualifier3:f2:q3, qualifier4:f2:q4, qualifier5:f2:q5, qualifier6:f3:q1, 
    qualifier7:f3:q2, qualifier8:f3:q3, qualifier9:f3:q4',
    row_id = 'rowId',
    hbase_table_name = 'hbaseNamespace:hbaseTable',
    external = false
);

Note

If user specifies hbase_table_name, then the schemaName must be same as the namespace in hbase_table_name when creating a table. Otherwise, the creation will be failed.

Example (failure to create table):

CREATE TABLE default.typeMapping (
    rowId         VARCHAR,
    qualifier1     INTEGER
)
WITH (
    column_mapping = 'rowId:f:rowId, qualifier2:f1:q2',
    row_id = 'rowId',
    hbase_table_name = 'hello:type4'
);

When creating a table to link with HBase cluster, you must ensure that the schema name in HBase connector and HBase data source are the same and achieve the same isolation level.

Drop Table

DROP TABLE schemaName.tableName;

Rename Table

ALTER TABLE schemaName.tableName RENAME TO schemaName.tableNameNew;

Note

Currently, it does not support renaming the tables which are created through HBase.

Add Column

ALTER TABLE schemaName.tableName
ADD COLUMN column_name INTEGER 
WITH (family = 'f1', qualifier = 'q1');

Note

Currently, deleting columns is not supported

Delete row/rows

DELETE FROM schemeName.tableName where rowId = xxx;
DELETE FROM schemeName.tableName where qualifier1 = xxx;
DELETE FROM schemeName.tableName;

Limitations

Statement show tables can only display the tables that the user has established the associations with HBase data source. Because HBase does not provide an interface to retrieve metadata of tables.