Apache HBase Writing Data Best Practices

For writing data into HBase, you use methods of the HtableInterface class. You can also use the Java API directly, or use the HBase Shell Commands. When you issue an HBase Shell Put command, the coordinates of the data are the row, the column, and the timestamp. The timestamp is unique per version of the cell, and it can be generated automatically or specified programmatically by your application, and must be a long integer. In this article, we will check Apache HBase writing data best practices to tune the performance…

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Hive CREATE INDEX to Optimize and Improve Query Performance

The main goal of creating INDEX on Hive table is to improve the data retrieval speed and optimize query performance. For example, let us say you are executing Hive query with filter condition WHERE col1 = 100, without index hive will load entire table or partition to process records and with index on col1 would load part of HDFS file to process records. But be informed that Index on hive table is not recommended. The create index will help if you are migrating your existing data warehouse to Hive and…

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Hive Create View Syntax and Examples

You can use Hive create view to create a virtual table based on the result-set of a complex SQL statement that may have multiple table joins. The CREATE VIEW statement lets you create a shorthand abbreviation for a more complex and complicated query. Apache Hive view is purely a logical construct (an alias for a complex query) with no physical data behind it. Note that, Hive view is different from lateral view.  Read: Hive CREATE INDEX to Optimize and Improve Query Performance Hadoop Hive Bucket Concept and Bucketing Examples Hive…

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Teradata Split Delimited Fields into Table Records and Examples

If you are working on the huge amount of different source system then you may come across the requirement of Teradata split delimited fields into table records. You can perform Teradata split delimited string into columns in various ways using Teradata built-in string functions or Teradata regular expressions. You can use any of the below methods as per your requirements: Teradata Split Delimited fields using STRTOK_SPLIT_TO_TABLE Function  Since TD14, there is a STRTOK_SPLIT_TO_TABLE function. You can use this function to split your string or delimited field into table columns. Teradata…

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Teradata Regular Expressions and Examples

The Teradata regular expressions functions identify precise patterns of characters and are useful for extracting string from the data and validation of the existing data, for example, validate date, range checks, checks for characters, and extract specific characters from the data. In this article, we will check some of commonly used Teradata regular expressions. Read: Teradata String Functions and Examples Commonly used Teradata date functions and Examples Teradata Substring Regular Expression - REGEXP_SUBSTR This function is used to extracts a substring from source_string that matches a regular expression specified by…

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Teradata String Functions and Examples

Teradata String Functions are primarily used for various string manipulation. It also supports most of the standard string function along with the Teradata extension to those functions. Teradata String Functions Below are the commonly used Teradata string functions: Read: Teradata Regular Expressions and Examples Teradata Set Operators: UNION, UNION ALL, INTERSECT, EXCEPT/MINUS Commonly used Teradata Analytics Functions and Examples Teradata Date Functions and Examples Function Description concat(string1, ..., stringN) Returns the concatenation of two or more string values. This function provides the same functionality as the SQL-standard concatenation operator (||). length(string) Returns…

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Access HBase Tables from Impala working Examples

As you know Hadoop Hive or Impala does not properly support transaction data. HBase is best suited for the table which required lot of delete, update, insert etc. You may want to explore the data stored in the HBase table. This article, helps you to understand how to access HBase tables from Impala and we will check out process with an example. Read other article on loading HBase table from Hive: Loading HBase Table from Apache Hive Why you want to access the HBase tables from Impala? This is obvious…

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Cloudera Impala Type Conversion Functions and Examples

Impala has some very strict rules regarding data types for function parameters that you provide while executing it. Impala type conversion functions are used to explicitly convert the required format. For example, Impala does not convert DOUBLE to FLOAT, INT to STRING etc. In my other post, we have discussed on Impala date functions and examples. In this article, we will check out Cloudera Impala type conversion functions with an examples. Read: Commonly used Cloudera Impala Date Functions and Examples Impala Type Conversion Functions These type conversion functions uses common…

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Clouderal Impala SQL Join Types and Examples

Impala SQL Join is a clause that is used for combining specific fields from two or more tables based on the common columns. The joins in the Impala are similar to the SQL and Hive joins. Joins are used to combine rows from multiple tables. In this article, we will learn about different Impala SQL join types with examples. Different Impala Join Types Following are Different Hive Join Types INNER JOIN LEFT OUTER JOIN RIGHT OUTER JOIN FULL OUTER JOIN SEMI JOIN ANTI JOIN CROSS JOIN Below are the tables…

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Access Netezza Database, Tools and Examples

There are many ways to access Netezza database or host. You can use the nzsql command, you can also access the Netezza system by using tools such as Aginity, Squirrel and from windows system using nzsql.exe program if you have Netezza ODBC drivers installed. Access Netezza Database using nzsql Command You can use the nzsql command on the IBM Netezza host system or from a UNIX client system that can access the Netezza host. The client system should be configured with Netezza drivers in order to access the Netezza host.…

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