https://community.cloudera.com/t5/Support-Questions/How-HCatalog-is-different-from-Hive/m-p/215292#M177202 <P>Let's start with <EM>Hive</EM> and then <EM>HCatalog.</EM></P><P><STRONG>Hive</STRONG> </P><UL> <LI>Layer for analyzing, querying and managing large datasets that reside in Hadoop various file systems</LI></UL><P>⇢ uses <EM>HiveQL</EM> (HQL) as processing engine</P><P>⇢ uses <EM>SerDes</EM> for serialization and deserialization</P><P>⇢ works best with huge volumes of data</P><P><STRONG>HCatalog</STRONG></P><UL> <LI>Table and storage management layer for Hadoop</LI></UL><P>⇢ basically, the <EM>EDW</EM> system for Hadoop (it supports several file formats such as <EM>RCFile</EM>, <EM>CSV</EM>, <EM>JSON</EM>, <EM>SequenceFile</EM>, <EM>ORC)</EM></P><P>⇢ is a sub-component of Hive, which enables ETL processes</P><P>⇢ tool for accessing metadata that reside in <EM>Hive Metastore</EM></P><P>⇢ acts as an API to expose the metastore as REST interface to external tools such as Pig</P><P>⇢ uses <EM>WebHcat</EM>, a web server for engaging with the <EM>Hive Metastore</EM></P><P>I think the focus has to be made on how they complement each other rather than focusing on their differences.</P><P>Documentation (3)</P><UL> <LI>This <A href="https://community.hortonworks.com/questions/23797/how-the-hive-metastore-works.html">answer</A> from <A rel="user" href="https://community.cloudera.com/users/186/sshaw.html" nodeid="186">@Scott Shaw</A> is worth checking</LI><LI>This <A href="https://fr.slideshare.net/markgrover/introduction-to-hive-and-hcatalog">slideshare</A> presents the use cases and features of <EM>Hive</EM> and <EM>Hcatalog</EM></LI><LI>This direct <A href="https://www.ibm.com/support/knowledgecenter/en/SSKKZM_1.3.0/fuwucon_forward_hadoop.htm">graph</A> from IBM shows how they use both layers in a <EM>batch job</EM></LI></UL><P>I hope this helps! <span class="lia-unicode-emoji" title=":slightly_smiling_face:">🙂</span></P> Mon, 10 Dec 2018 09:58:52 GMT zaki 2018-12-10T09:58:52Z