Thanks Cheng for the great explanation!
bit1...@163.com From: Cheng Lian Date: 2015-03-16 00:53 To: bit1...@163.com; Wang, Daoyuan; user Subject: Re: Explanation on the Hive in the Spark assembly Spark SQL supports most commonly used features of HiveQL. However, different HiveQL statements are executed in different manners: DDL statements (e.g. CREATE TABLE, DROP TABLE, etc.) and commands (e.g. SET <key> = <value>, ADD FILE, ADD JAR, etc.) In most cases, Spark SQL simply delegates these statements to Hive, as they don’t need to issue any distributed jobs and don’t rely on the computation engine (Spark, MR, or Tez). SELECT queries, CREATE TABLE ... AS SELECT ... statements and insertions These statements are executed using Spark as the execution engine. The Hive classes packaged in the assembly jar are used to provide entry points to Hive features, for example: HiveQL parser Talking to Hive metastore to execute DDL statements Accessing UDF/UDAF/UDTF As for the differences between Hive on Spark and Spark SQL’s Hive support, please refer to this article by Reynold: https://databricks.com/blog/2014/07/01/shark-spark-sql-hive-on-spark-and-the-future-of-sql-on-spark.html Cheng On 3/14/15 10:53 AM, bit1...@163.com wrote: Thanks Daoyuan. What do you mean by running some native command, I never thought that hive will run without an computing engine like Hadoop MR or spark. Thanks. bit1...@163.com From: Wang, Daoyuan Date: 2015-03-13 16:39 To: bit1...@163.com; user Subject: RE: Explanation on the Hive in the Spark assembly Hi bit1129, 1, hive in spark assembly removed most dependencies of hive on Hadoop to avoid conflicts. 2, this hive is used to run some native command, which does not rely on spark or mapreduce. Thanks, Daoyuan From: bit1...@163.com [mailto:bit1...@163.com] Sent: Friday, March 13, 2015 4:24 PM To: user Subject: Explanation on the Hive in the Spark assembly Hi, sparkers, I am kind of confused about hive in the spark assembly. I think hive in the spark assembly is not the same thing as Hive On Spark(Hive On Spark, is meant to run hive using spark execution engine). So, my question is: 1. What is the difference between Hive in the spark assembly and Hive on Hadoop? 2. Does Hive in the spark assembly use Spark execution engine or Hadoop MR engine? Thanks. bit1...@163.com
