Many commands can check the memory utilization of JAVA processes, for example, pmap, ps, jmap, jstat. What are the differences? Before we ...

Hive table contains files in HDFS, if one table or one partition has too many small files, the HiveQL performance may be impacted. Sometime...

This article shows a sample code to load data into Hbase or MapRDB(M7) using Scala on Spark. I will introduce 2 ways, one is normal load us...

This is a cookbook for scala programming. 1. Define a object with main function -- Helloworld. object HelloWorld { def main(args: Array...

Hive is trying to embrace CBO(cost based optimizer) in latest versions, and Join is one major part of it. Understanding join best practices ...

Goal: How to build and use parquet-tools to read parquet files. Solution: 1. Download and Install maven. Follow below link: http://...

Goal: This article explains the configuration parameters for Oozie Launcher job.

Goal: How to control the number of Mappers and Reducers in Hive on Tez.

Env: PostgreSQL or Greenplum Symptom: COPY from a file into a table fails with error: ERROR: invalid byte sequence for encoding "...

Goal: This article research on how Spark calculates the Decimal precision and scale using GPU or CPU mode. Basically we will test Addition/S...