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Hbase Reflexions

hbase looks a powerfull tool in complement of hive. While hive suits well for ETL and data historisation, it cannot offer sub-second access to thousand of concurrent users.

Hbase comes with a powerful compagnion aka Phoenix that provides many features, while keeping the hbase features intact. Phoenix provides a jdbc driver to hbase. This distinction adds many improvements:

  1. it offers sql, joins, secondary indexes, transactions, sequences on top of hbase.
  2. it simplifies hive, spark, solr, and general programming access to hbase data.

JDBC overview

jdbc access can be done with kerberos on the form

"jdbc:phoenix:thin:url=<scheme>://<server-hostname>:<port>;authentication=SPNEGO;principal=my_user;keytab=/home/my_user/my_user.keytab"

Phoenix connection thought JDBC needs : - a jdbc jar file - the hbase-site.conf - a kerberos ticket

Phoenix does not provide a way for connection pooling. The costly part of the connection is the hbase link. However it is cached within the region servers and a new phoenix jdbc connection can be rebuild for every query since it is a lightweight object.

Hive integration

Phoenix tables can be mounted into hive thanks to a recent plugin. In comparaison to hbase plugin, this allows fast join to hive table (to be tested). While this plugin needs phoenix 4.8.0+ HDP ships with phoenix 4.7.0. However HDP Phoenix is a fork of Phoenix, and it integrates this feature.

Because phoenix allows to mount a hbase table, hive a phoenix or a hbase table, there is many ways to make hive querying hbase. Moreover hive can create a regular table stored as a hbase or phoenix table wich is slightly different. The best way is to mount phoenix as a hive external table. First advantage is phoenix allows salted tables by mean there is no need to manually handle the key to be well distributed. Second, is loading directly into phoenix allows it to manage its secondary indexes and also some other tools such solr.

Finally, hive can access an external phoenix table and allow both upsert and select. The plugin also provides a way to delete/update from hive, however I haven't been able to reproduce yet since transactional tables are only compatible with orc based tables.

Spark integration

Spark can read and write from phoenix here on SOF or here on official. The good point is it can be done from scala or python.

Solr integration

Solr integration with hbase is a good idea: hbase contains the truth and solr allows fast lookup to discover it. However, setting up solr on top of hbase is a pain. Phoenix simplifies drastically that : here

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