Netezza

Netezza Analytic Functions

Netezza analytic functions compute an aggregate value that is based on a group of rows. A Netezza SQL analytic function works on the group of rows and ignores the NULL in the dat.  Netezza server is basically an analytics system and provides many useful functions that can perform day to day aggregations. As these functions are native to Netezza server, hence use of these Netezza analytic functions improves performance of SQL queries as well as server performance. Frequently used Netezza analytical functions are as follows: COUNT Analytic Function Returns the number of…

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August 17, 2016
Netezza

Netezza Joins and it’s Algorithms

Netezza joins combines the columns of the reports from the more than one table. SQL JOIN clause is used to combine rows from two or more tables, based on a common field between them. The best way to understand the Netezza joins is to get to know the SQL joins and then consider the algorithm that is used by database to resolve them. Read: Netezza nzsql Command and its Usage Netezza Generate Statistics: A Guide and Best Practices Commonly used Netezza Utilities Netezza Joins: Equi Join An equijoin is a join…

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August 14, 2016
Netezza

Netezza Generate Statistics: A Guide and Best Practices

Netezza uses the cost based optimizer to determine best methods determine redistribution, scan, join, join orders. The optimizer uses statistics information to determine the most efficient way to run a query. System uses the Netezza GENERATE STATISTICS command to generate information about each column proportion of the duplicate values,unique values, NULL values and the maximum and minimum values. How Statistics are collected? Netezza system collects statistics in various ways: Statistics are automatically generated for certain database operations Collect full statistics by running Netezza GENERATE STATISTICS command. This operation is required when table changes significantly, say…

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August 13, 2016
Netezza

Netezza nzsql Command and its Usage

The Netezza nzsql command invokes a SQL command interpreter on the Netezza host or any Unix/Linux system that can act as a edge node to connect to Netezza host. Read: Netezza Basic Commands Commonly used basic Netezza Linux Commands You can use the nzsql command to perform all the sql related stuffs. E.g. create database objects, run queries, and manage various databases created on that particular server. You cannot manage the object created in different host or server. Read: nzload Command and its Usage in Netezza Netezza nzsql Internal Slash…

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August 12, 2016
Netezza

Analyze and Optimize Netezza Query Performance

Analyze and Optimize Netezza Query Performance is very important part if you are performing the reporting on top of Netezza or processing large amount of data. Netezza query tuning is very important part to improve performance. Netezza uses cost based optimizer to determine the best methods for scan and join operations, orders and redistribute or broadcast operations. Netezza system may redistribute the data for some situations like joins, grouping aggregates, create tables and when loading data into Netezza tables. System will decide the redistribution based on the cost like table…

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August 11, 2016
Netezza

Netezza Sequence and how to Create/Use it

A Netezza sequence is named objects in an individual database in Netezza, that can provide the unique value when get next value method. You can use sequence to generate unique numbers that can be used as surrogate key values for primary key values. Netezza Sequence Overview A sequence value is an integer that you can use wherever you would use numeric values. Netezza supports user sequences for the four integer types: byteint, smallint, integer, and bigint. You can even create a sequence with an initial value, an increment, a minimum and a maximum value.…

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July 7, 2016
Netezza

Working with Netezza Zone Maps and Best Practices

Before going to Netezza zone maps first let’s understand extent.  An extent is smallest unit of storage on the disk. In fact it is smallest disk allocation on storage to store the data. Netezza would maintain the maximum and minimum value of the column that is stored in an extent (each extent is of 3MB in size) What are Netezza Zone maps? Netezza Zone maps is an internal mapping structure to the extent (smallest unit of storage) that takes advantage of internal ordering of the data.  These are automatically generated internal…

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July 6, 2016
Netezza

Netezza FPGA – FAST Framework in Netezza

Most of the companies around the globe using Netezza data warehouse appliance to perform their near real-time, complex analytics and data warehouse needs. Netezza FPGA is important part of NPS system. NPS performance is made of a result of framework of Netezza FPGA Accelerated streaming technology (FAST) engine. This engine is just like a turbo-charger to an already powerful engine. This FAST engine what makes the Netezza a powerful server. Read: Working with Netezza Zone Maps nzload command and its Usage nzsql Command and its Usage Netezza has introduced a FAST…

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July 5, 2016