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Note: All the posts are based on practical approach avoiding lengthy theory. All have been tested on some development servers. Please don’t test any post on production servers until you are sure.

Tuesday, February 06, 2018

Integrating Hadoop Cluster with Microsoft Azure Blob Storage


Azure Blob storage is a service for storing large amounts of unstructured object data, such as text or binary data, that can be accessed from anywhere in the world via HTTP or HTTPS. You can use Blob storage to expose data publicly to the world, or to store application data privately. All access to Azure Storage is done through a storage account. 

Monday, January 29, 2018

Install SQL Server 2017 on Linux [RHEL]

SQL Server 2017 now runs on Linux. It’s the same SQL Server database engine, with many similar features and services regardless of your operating system.

I'm providing below the straight away installation for it.

Thursday, January 25, 2018

Using Avro with Hive and Presto


The AvroSerde allows users to read or write Avro data as Hive tables. The AvroSerde's bullet points:

Working with Apache Avro to manage Big Data Files

What is Avro?

Apache Avro is a language-neutral data serialization system and is a preferred tool to serialize data in Hadoop. Serialization is the process of translating data structures or objects state into binary or textual form to transport the data over network or to store on some persistent storage. Once the data is transported over network or retrieved from the persistent storage, it needs to be deserialized again.

Custom Merge Utility for Flume Generated Files


My client is streaming tweets to HDFS location, thousands of flume files are being created on this location. Hive External Table has been created on this location, external table performance is degraded when there are too may small files.

Tuesday, January 23, 2018

How to merge multiple part files (ORC) in Hadoop created by PolyBase?


One of my client is using PolyBase to query and offloading SQL Server data to Hadoop. While offloading data in Hive ORC format, multiple part files are created by the PolyBase in HDFS. For better query performance all these part files are needed to be merged.

Sunday, January 21, 2018

Using Microsoft PolyBase to query Big Data


PolyBase is a technology that accesses data outside of the database via the t-sql language. In SQL Server 2016, it allows you to run queries on external data in Hadoop or to import/export data from Azure Blob Storage. Queries are optimized to push computation to Hadoop. PolyBase does not require you to install additional software to your Hadoop environment. Querying external data uses the same syntax as querying a database table. This all happens transparently. PolyBase handles all the details behind-the-scenes, and no knowledge about Hadoop is required by the end user to query external tables.

Monday, January 08, 2018

Processing Twitter (JSON) Data in Oracle (12c External Table)


  • We have live Twitter stream data ingested by Flume to our Hadoop cluster. 
  • Flume is generating too many files in HDFS, 2 files in 1 second about 172k files in a day.
  • We have to process the Flume generated twitter JSON files.
  • Created an Oracle external table over twitter JSON files but performance is too bad because of too many files.
  • Need a remedy for the above issues.

Thursday, January 04, 2018

Using Preprocessor with External Table [Over HDFS]

Oracle 11g Release 2 introduced the PREPROCESSOR clause to identify a directory object and script used to process the files before they are read by the external table. This feature was backported to 11gR1 ( The PREPROCESSOR clause is especially useful for reading compressed files, since they are unzipped and piped straight into the external table process without ever having to be unzipped on the file system.

Partitioning Oracle (12c) External Table [Over HDFS]

Partitioned external tables were introduced in Oracle Database 12c Release 2 (12.2), allowing external tables to benefit from partition pruning and partition-wise joins. With the exception of hash partitioning, many partitioning and subpartitioning strategies are supported with some restrictions. In this post I've created a test to get better performance of external table over HDFS.

Optimizing NFS Performance [HDP NFS]


You may experience poor performance when using NFS. Careful analysis of your environment, both from the client and from the server point of view, is the first step necessary for optimal NFS performance. Aside from the general network configuration - appropriate network capacity, faster NICs, full duplex settings in order to reduce collisions, agreement in network speed among the switches and hubs, etc. - one of the most important client optimization settings are the NFS data transfer buffer sizes, specified by the mount command options rsize and wsize.