How to fix ERROR 1045 : Access denied for user 'root'@'localhost' (using password: YES)

Please follow below steps to fix HDP Sandbox -Mysql root password issue: Enter mysql -u root UPDATE mysql.user SET Password=PASSWORD('hadoop') WHERE User='root'; FLUSH PRIVILEGES...

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How to Prepare and Clear Hortonworks Data Platform Certified Developer Exam (HDPCD -English)

 HORTONWORKS UNIVERSITY is offering HDPCD certificate and its exclusively hands-on, performance-based exam that require we to complete a set of tasks on actual hadoop cluster instead of just guessing multiple choice questions. Basically HDPCD certificate categorised into 3 categories 1. Data ingestion 2. Data transformation 3. Data analysis As...

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How to use Password file with Sqoop

How to use local password-file parameter with sqoop Problem: sometimes we have to read password from file for sqoop command. Solution: Passing password parameter file to sqoop command is not a big deal. Just follow below steps: 1.    Create a password with Echo -n “<<password>> > <<passwordfilename>> E.g....

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SQOOP-SqlManager-Error reading from database-java.sql.SQLException-set com.mysql.jdbc.RowDataDynamic-3c2d5cfb

Problem: sqoop export --connect "jdbc:mysql://sandbox.hortonworks.com:3306/hdpcdpractise" --username hadoop --password hadoop --table weather --export-dir /user/hortonworks/weather/  --fields-terminated-by ','; Some times...

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How to create a column in a table and that should throw error when we do SELECT * or SELECT col

Problem: Create a column in a table and that should give an error if we give SELECT * or SELECT of that column Solution: Friends, don’t think toooooo much like how to solve this problem. Here is the simple solution that I got. Just use any computed column and that should not have any syntactical errors but it should have logical error (E..g...

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Greenplum System-Useful Queries

Useful Queries: Query to verify the list of segments in a Greenplum system select * from gp_segment_configuration; Result: Column Value Description Content = -1 Master Node Content...

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Greenplum Best Practises

Best Practices: A distribution key should not have more than 2 columns, recommended is 1 column. While modeling a database, we need to make sure all the tables that gets involved in longer query execution are distributed...

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Greenplum Architecture

Parallel Processing:  Taking all the rows from table and spreading them among many parallel processing units. In greenplum these parallel  processing units are called segments. SMP(symmetric multi processing system):   A...

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How to find and delete the top 100 most used files in Linux/Unix

Steps to find and delete the top 100 most used files in Linux/Unix Command to find most disk space used files: find / -xdev -type f -size +100M -exec du -sh {} ';' | sort -rh | head -n100 Command to delete the content without removing the file > <<filename>> E.g. > sample.txt Here > is used to empty the file Thanks...

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How to Install MySQL on CentOS 7

Steps to Install MySQL on Linux-CentOS 7 Step 1: Download MYSQL repositories wget http://dev.mysql.com/get/mysql57-community-release-el7-9.noarch.rpm Step 2: Prepare repository to install MySQL sudo rpm -Uvh mysql57-community-release-el7-9.noarch.rpm Step...

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