Netezza Archives - Page 16 of 17

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

Working with Materialized Views in Netezza

When you create a materialized views from a base table, the Netezza system stores the view definition for the lifetime of the SPM view and is visible as a materialized view. SPM view data slices are co-located on the same data slices as the corresponding base table data slices hence increases the performance of the query. A materialized views reduces the width of number of columns being scanned in a base table, these type of view contains a small subset of frequently queried columns. When you query the table (table with large number of…

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August 7, 2016

Netezza

How to install vmware player and Netezza Emulator on ubuntu

The Netezza emulator is an emulated Netezza appliance that runs both a virtual host and a virtual S-Blade. It is a fully functional system to be used for initial development and testing only. This tool should never be used in the PRODUCTION environment. It is simply a tool for developers only and you cannot use it for performance optimization. You can use this tool to learn the Netezza appliance. Note: This tutorial is tested on the ubuntu 14.04 Useful Netezza Emulator Information Short information that you might want to know before start using Netezza emulator You should treat…

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August 4, 2016

Netezza

Working with Netezza Stored Procedures

Netezza stored procedures are used to encapsulate the business logic and same time handle the exceptions. SQL provides the power to get and update the database information on the host server, and the procedure language provides the logic for if-then-else branching and application processing on the data. Read: Netezza RECORD Type Variable, Usage and Examples Netezza Stored Procedure ARRAY Variables and Examples For example, you may want to check the table if its existed in database before dropping it. You achieve this by creating stored procedure. e.g. CALL DROP_IF_EXIST(table_name); if you…

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July 30, 2016

Netezza

Working with Netezza Clustered Base Tables (CBT)

A Netezza clustered base tables (CBT) are user table that has data which is organized using one to four organizing keys columns. You can specify max four columns in organize on clause and those columns should not be a part of distribute on clause. An organizing key is a column of the table that you specify for clustering the table records; organizing table helps Netezza to save records in same or nearby extents. You can organize the records using "ORGANIZE ON" clause. Netezza does create zone maps on organizing columns, which will accelerate the performance of queries on that…

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July 26, 2016

Netezza

Groom in Netezza Tables and Databases with Aginity

Before getting into how to groom Netezza table and database, first let’s understand what grooming is? Use the GROOM TABLE command to maintain the user tables by reclaiming disk space for deleted or outdated rows. You can also use GROOM TABLE command to reorganize the tables by their organizing keys columns. End user can execute DML statements such as SELECT, UPDATE, DELETE, and INSERT operations while the data grooming is running. The SELECT operations run in parallel with the grooming operations and any INSERT, UPDATE, and DELETE operations run serially between the…

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July 13, 2016

Netezza

Easy methods to Import data using Aginity

In this post, I am going to show you how to import data using Aginity workbench. Data import in Aginity workbench has fairly easy method to get data into Netezza system for those who are not familiar with nzload and external table options. Netezza import is one of important task in Neteza data warehouse. Read: Installing Aginity workbench Aginity workbench is an easy-to-use application that enhances performance and creates efficiencies when working with MPP data warehouse appliances. Aginity workbench provides a powerful set of GUI-based tools for developers, DBAs, and data analysts. Import…

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July 9, 2016

Netezza

How to Install Aginity Workbench for Netezza

I have received multiple requests to create tutorial on working with Netezza SQL database development tool. In this post, I have created guide to install Netezza Aginity workbench in windows environment. About Netezza Aginity Aginity workbench is an easy-to-use application that enhances performance and creates efficiencies when working with MPP data warehouse appliances. Aginity workbench provides a powerful set of GUI-based tools for developers, DBAs, and data analysts. Read: Access Netezza Database, Tools and Examples Netezza Groom Tables and Databases nzsql command and its Usage Netezza SET CATALOG command This SQL database…

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July 8, 2016