nzload Archives - DWgeek.com

Different Extraction Methods in Data Warehouse

Extraction is the first step of the ETL(Extract, Transform and Load) process. Once the data is extracted, you can transform it and load to target data warehouse. Extraction is the process of extracting data from the source system for further use in the data warehouse environment. Related Reading: Data Warehouse Fact Constellation Schema and Design Star Schema model in Data Warehouse Snowflake Schem Model in Data Warehouse Data warehouse is an OLAP system, typically source system includes the transaction business processing application. For example, it could be sales order entry…

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September 16, 2016

Netezza

Commonly used Netezza Utilities

It is very easy to perform the ETL (Extract, Transform and Load) functionalities in Netezza. Netezza supports utilities those can be used to perform the ETL/ELT operations. Below are some of commonly used Netezza utilities: Read: Commonly used Netezza Basic Commands nzload utility nzload is bulk data load utility available in Netezza. This utility supports loading data from flat file to Netezza database tables. Below is the syntax and usage: Usage: nzload -host <host> -db <database> -u <username> -pw <password> -t <target_table_name > -df /user/home/flat_file.txt by default, nzload supports '|'…

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September 4, 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

Importance of right Netezza Distribution key

This post is all about how data is distributed (Netezza distribution key) in Netezza server. Feel free to make comments or suggestions to improve it, or pass it on if you like. Let’s first understand how NPS stores the data on disk drives. Each Snippet Processor in the Snippet Processing Unit (SPU) has a dedicated hard drive has its separate CPU, FPGA, separate RAM memory, hard disks and the data on stored on drive is called a data slice. Read: Changing Netezza Table Distribution Key Cluster Based Tables (CBT) in…

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July 6, 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

A Guide to load data into Netezza Database

Netezza data load is transferring data into Netezza appliance. There are several ways to transfer the data into appliance. Netezza Data Load using External tables These are tables stored as flat files on the host or client systems and not in the Netezza appliance database. Create table on top of the flat file that needs to be loaded to Netezza tables, then use that external table to load target table in Netezza appliance. As a result data will be copied to the target table. Flat Files An external table allows…

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July 6, 2016

Netezza

nzload Command and its Usage in Netezza

nzload is bulk copy command available in Netezza. This is a command that provides an easy method for using external tables and getting data into the Netezza appliance. Read: guide to load data into Netezza Working with Netezza Zone Maps Commonly used Netezza Basic Commands Netezza COPY Command Syntax and Examples How the nzload Command Works? The nzload command is a SQL CLI client tool that allows you to load data from the local or a remote client, on all the supported client platforms (Linux/windows). The nzload command processes command-line…

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July 5, 2016