Apache Zeppelin is a multi-purpose software that can be used for data visualization, data ingestion, data discovery and data analytics. You can check the below mentioned URL to know more about it and to download the software. https://zeppelin.apache.org/ In download section, I’ll suggest to download the “Binary package with all interpreters” which provides number of interpreters that can be used to connect to various sources. In today’s tutorial, we will see: How to create interpreter to be used for Teradata in Zeppelin? How to connect to Teradata using interpreter and run queries? How to create simple pie-chart for data visualization report? Note: We assume youRead More →

As per SQL standards we cannot use ORDER BY clause in subqueries. It also does not make sense to use ORDER BY inside a derived table.Let’s see an SQL example to identify the problem and how to overcome it. This is a perfectly fine query: SELECT E_EMPNO,E_EMPNAME,E_MOB FROM EMPLOYEE ORDER BY 1,2; Now if we create a derived table using this query it will fail. SELECT COUNT(1) FROM ( SELECT E_EMPNO,E_EMPNAME,E_MOB FROM EMPLOYEE ORDER BY 1,2 )TBL1; Error–> 3706: Syntax error: ORDER BY is not allowed in subqueries. Possible Solutions: 1) Now the obvious solution could be to remove ORDER BY clause from the query.Read More →

Recently Raghav reached out to us on our Facebook page asking for a SQL query in Teradata to identify the highest AMPCPU, I/O and SPOOL usage for each hour during a given time period. He was actually working on some activity to find out the consumption of resources on Teradata box on hourly basis. The purpose was to find out time range when Teradata is most heavily loaded and when it is relatively free. He was looking for information in hourly manner for any given day or multiple days. Also he was referring to our post to check SQL Query Performance in Teradata however theRead More →

What is encryption ? Why we need encryption ? How do we implement encryption ? One must clearly know answer to these 3 questions before actually implementing encryption in any datawarehouse environment. Encryption is the process by which we change the actual meaningful value to some other meaningless value so that any person who reads it cannot understand it. For example if I say “VGTCFCVC” it won’t make any sense to you however if I share actual value “TERADATA” then you’ll immediately understand it. We may use any algorithm to convert one value to other ranging from very simple to extreme complex. In this caseRead More →

We recently received a comment on our previous TPT post,(Click here to read it) requesting for a sample TPT script to load multiple data files into one single Teradata Table using Load operator.The TPT script is simple and is very much similar to our TPT script we shared in earlier posts. The main component which will change is the PRODUCER operator. Here we’ll use 2 new variables : VARCHAR FileList = ‘YES’, VARCHAR FileName = @File1 FileList : represent here that we are going to process list of files. FileName: the Filename which has list of DATA files in it. One in each line. SoRead More →

ROWS-DISTRIBUTION-IN-TERADATA

How Teradata distribute rows ? It is very important to understand how Teradata actually distribute rows among AMPs. We all know that PRIMARY INDEX is used for data distribution. All the AMPs in the Teradata system maintains a portion of each table and this forms the basis of ‘parallel architecture and share nothing‘ architecture of Teradata. We will see how exactly it happens and what all hash functions are used to determine the respective AMP which will hold the table. There are three main functions: HASHROW: The function returns 4 BYTE output for each input value. So the primary index value is passed through HASHROWRead More →

Do you want to learn Teradata however have no clue how to start and what all to read then this post is for you. We receive so many requests from our blog readers asking if we can help them in learning Teradata. And when we ask what exactly they want to learn or any specific topic in Teradata they are looking for then they go mum. Understanding all the aspects of TERADATA RDBMS is not simple and definitely requires good time. You cannot become expert in a day or two. So I thought of writing a blog which should help in figuring out what allRead More →