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Any blog which is technical will follow here

Oracle listener configuration architecture - database instance connected to multiple clients through TNS listener port 1521

How to Configure Oracle Listener for Standalone Database: Step-by-Step Guide

Posted on by sanjeeva

The Problem: TNS-12541 and Database Connection Failures You’ve just installed Oracle 19c on your server. The database is up and running perfectly—you can connect locally using SQL*Plus without any issues. But the moment you try connecting from a remote application or another server, you’re hit with the dreaded TNS-12541: TNS:no listener error. Sound familiar? This Read more about How to Configure Oracle Listener for Standalone Database: Step-by-Step Guide[…]

ORA-01555 snapshot too old error with UNDO tablespace configuration and retention fix for Oracle 19c

ORA-01555: Snapshot Too Old – Complete Fix Guide for Oracle 19c

Posted on by sanjeeva

The Problem: Long-Running Query Fails with ORA-01555 You’re running a critical report or data export, and after 30 minutes it fails with: When this happens: The query was working fine yesterday. The data hasn’t changed much. But today it fails with ORA-01555. This guide shows you exactly how to fix it permanently. What is ORA-01555 Read more about ORA-01555: Snapshot Too Old – Complete Fix Guide for Oracle 19c[…]

ORA-12154: TNS Could Not Resolve the Connect Identifier – Complete Fix Guide

Posted on by sanjeeva

The Problem: Cannot Connect to Oracle Database You’re trying to connect to your Oracle database and you get this error: When this happens: You check the database – it’s running. You check the listener – it’s up. But nothing connects. This is ORA-12154, and it means Oracle can’t find or read your TNS configuration. Let Read more about ORA-12154: TNS Could Not Resolve the Connect Identifier – Complete Fix Guide[…]

Migrating Oracle 19c Database from Local Storage to ASM: A Complete Step-by-Step Guide

Posted on by sanjeeva

Last Updated: December 2025 | Oracle 19c | ASM Grid Infrastructure Have you ever encountered a frustrating situation where your Oracle database is running on local storage, and you need to migrate everything to ASM (Automatic Storage Management) without significant downtime? Recently, we faced this exact scenario with a production Oracle 19c Container Database (CDB) Read more about Migrating Oracle 19c Database from Local Storage to ASM: A Complete Step-by-Step Guide[…]

ORA-00257: Archiver Error Connect Internal Only Until Freed – Complete Resolution Guide

Posted on by sanjeeva

Introduction Have you ever encountered a situation where your Oracle database suddenly stops accepting new connections, and users start complaining that the application is down? One of the most common culprits behind this scenario is the dreaded ORA-00257: archiver error. Recently, we faced this exact scenario with one of our production databases during a high-transaction Read more about ORA-00257: Archiver Error Connect Internal Only Until Freed – Complete Resolution Guide[…]

Oracle ASM 19c architecture diagram showing containerized databases using Oracle ASM for shared storage management with disk groups

Oracle ASM 19c Installation: Complete Guide to Oracle Restart Grid Infrastructure [2025]

Posted on by sanjeeva

Last Updated: December 10, 2025Tested On: Oracle Enterprise Linux 9.5, Oracle ASM 19c Patch 25 Oracle Automatic Storage Management (ASM) provides a robust storage management solution for Oracle databases. In this comprehensive guide, we’ll walk through ASM 19c Installation (patch set 25) in a standalone “Oracle Restart” grid infrastructure configuration on Oracle Enterprise Linux (OEL) Read more about Oracle ASM 19c Installation: Complete Guide to Oracle Restart Grid Infrastructure [2025][…]

Response file for Oracle ASM Standalone Oracle 19c

Posted on by sanjeeva

Introduction Response file for Oracle ASM Standalone is a critical thing to understand if you want to install this using CLI. This blog shows how to install Oracle 19c Grid Infrastructure in standalone (Oracle Restart) mode using a response file from CLI without any GUI. This is particularly helpful for DBAs working on headless servers Read more about Response file for Oracle ASM Standalone Oracle 19c[…]

How to Enable Archive Log Mode in Oracle 19c (Complete Guide)

Posted on by sanjeeva

Introduction Need to enable archive log mode in Oracle 19c but unsure of the exact steps? Converting from NOARCHIVELOG to ARCHIVELOG mode is essential for production databases, yet many DBAs hesitate due to concerns about downtime and configuration complexity. In this guide, I’ll walk through the complete process of enabling archive log mode in Oracle Read more about How to Enable Archive Log Mode in Oracle 19c (Complete Guide)[…]

Oracle Database Memory Monitoring Guide

Posted on by sanjeeva

Introduction Database memory management is crucial for maintaining optimal performance in Oracle databases. Inefficient memory usage can lead to slower query execution, increased I/O operations, and poor application response times. This comprehensive guide provides database administrators and developers with practical tools and techniques for monitoring and optimizing Oracle database memory components. Why Memory Monitoring Matters Read more about Oracle Database Memory Monitoring Guide[…]

PostgreSQL Schema Resolution Issues in ETL Processes

Posted on by sanjeeva

Have you ever encountered a frustrating situation where your PostgreSQL function works perfectly when executed directly but fails through your ETL tool? Recently, we faced this exact scenario with our Database (dv_d), and I wanted to share our investigation and solution to help others facing similar issues. This turned out to be a PostgreSQL schema Read more about PostgreSQL Schema Resolution Issues in ETL Processes[…]

How to Export NLS_DATE_FORMAT in Oracle: Data Pump Import Date Format Fix

Posted on by sanjeeva

The Problem: Data Pump Import Fails with Date Format Error You’re running a Data Pump import and it crashes with date format errors like ‘1998-01-01 00:00:00′. You try setting export NLS_DATE_FORMAT=’YYYY-MM-DD HH24:MI:SS’ in your shell, but the import still fails. Error you’re seeing: This happens because Data Pump doesn’t always respect environment-level NLS settings, especially Read more about How to Export NLS_DATE_FORMAT in Oracle: Data Pump Import Date Format Fix[…]

How to Set Up PostgreSQL Read-Only User Permissions

Posted on by sanjeeva

Are you struggling with PostgreSQL read-only user permissions? This step-by-step guide will show you exactly how to create and configure read-only users in PostgreSQL 16. Whether you’re a database administrator or developer, you’ll learn how to properly set up schema-level permissions and avoid common pitfalls. The Challenge: PostgreSQL Read-Only Access Not Working Many developers face Read more about How to Set Up PostgreSQL Read-Only User Permissions[…]

Installing PostgreSQL 16 on RHEL 9 using DNF package manager with step-by-step terminal commands

How to Install PostgreSQL 16 on RHEL 9/Red Hat Linux [2025 Guide]

Posted on by sanjeeva

Last Updated: December 10, 2025Tested On: RHEL 9.3, PostgreSQL 16.1 PostgreSQL 16 is the stable release of the powerful open-source relational database system, offering enhanced performance, security, and new features. This comprehensive guide walks you through installing PostgreSQL 16 on RHEL 9 with step-by-step instructions, commands, and best practices. Why Upgrade to PostgreSQL 16 on Read more about How to Install PostgreSQL 16 on RHEL 9/Red Hat Linux [2025 Guide][…]

Generative AI for Databases: Transforming Data Management

Posted on by sanjeeva

Introduction For decades, relational databases have been the backbone of enterprise data management, relying on predefined schemas, manual query optimization, and structured data patterns. However, the emergence of generative AI is fundamentally transforming this landscape. By introducing capabilities like intelligent data synthesis, automated performance tuning, and adaptive query processing, AI is evolving databases from passive Read more about Generative AI for Databases: Transforming Data Management[…]

ASMSNMP User Setup: Complete Oracle ASM Monitoring Guide

Posted on by sanjeeva

Have you ever encountered a frustrating situation where your Oracle Enterprise Manager couldn’t monitor your ASM environment, leaving you blind to storage issues? Recently, we faced this exact scenario with a client’s production ASM cluster, and ASMSNMP user comes to rescue. The ASMSNMP user plays a crucial role in Oracle ASM (Automatic Storage Management), primarily Read more about ASMSNMP User Setup: Complete Oracle ASM Monitoring Guide[…]

PostgreSQL Performance Tuning: Complete Guide to Database Configuration (2025)

Posted on by sanjeeva

Introduction Is your PostgreSQL database running slowly? You’re not alone. 73% of database performance issues stem from misconfigured parameters. In this complete guide, you’ll learn the exact settings used by Netflix, Uber, and Instagram to handle millions of queries per second. In the next 15 minutes, you’ll discover: ✅ The 5 critical parameters that impact Read more about PostgreSQL Performance Tuning: Complete Guide to Database Configuration (2025)[…]

How to Increase Swap Size in Linux: A Complete Guide

Posted on by sanjeeva

Introduction Managing swap space efficiently is essential for optimal Linux performance, especially when handling memory-intensive applications. Sometimes, Oracle databases or Oracle Enterprise manager or any other application which is asking for swap will fail installations. This guide covers three common scenarios to Increase swap size in Linux: Follow these step-by-step instructions to optimize your system’s Read more about How to Increase Swap Size in Linux: A Complete Guide[…]

Resolving Pluggable Database (PDB) Opening in RESTRICTED MODE (ORA-65177) in Oracle 19c

Posted on by sanjeeva

Introduction Encountering, ORA-65177 ,a Pluggable Database (PDB) that opens in RESTRICTED mode can cause operational challenges, especially when working in a multitenant environment. This issue is often linked to synchronization failures between the Container Database (CDB) and its associated PDBs. We will delve into the root cause of the problem and provide a step-by-step resolution. Read more about Resolving Pluggable Database (PDB) Opening in RESTRICTED MODE (ORA-65177) in Oracle 19c[…]

Mastering PSQL: Enable Timings and Fetch All Rows Without Paging

Posted on by sanjeeva

PostgreSQL’s interactive terminal, psql, is an incredibly powerful tool for managing databases and executing queries. In this blog, we’ll discuss how to measure query execution time using “timing” and fetch all rows of a query result without paging using “\pset pager off”`. Let’s dive in step-by-step. Why Enable Timing in PSQL? When optimizing your SQL Read more about Mastering PSQL: Enable Timings and Fetch All Rows Without Paging[…]

From Regulation to Responsibility: Understanding the EU’s AI regulation

Posted on by sanjeeva

Introduction Artificial Intelligence (AI) has rapidly transformed various aspects of our lives, from personalized recommendations to autonomous vehicles. However, with great power comes great responsibility. The European Union (EU) recognizes the need to strike a balance between fostering AI innovation and safeguarding fundamental rights. On March 13, 2024, the EU took a significant and bold step Read more about From Regulation to Responsibility: Understanding the EU’s AI regulation[…]

The World of Generative AI: An Introductory Exploration

Posted on by sanjeeva

Generative AI! If you’ve ever marveled at a piece of artwork created by an AI, or interacted with a chatbot that seemed almost human, then you’ve already had a glimpse into what Generative AI can do. Welcome to this fascinating world of Gen AI! Generative AI is a subset of artificial intelligence that focuses on Read more about The World of Generative AI: An Introductory Exploration[…]

Optimizer Access Paths: index unique scan

Posted on by sanjeeva

In our previous blog, we have talked about the optimizer access path. In the last few blogs, we have explained different access paths. In this blog, we will see how the index unique scan works. Index unique scan is the optimizer access path where the database returns at most one row. It reads the index Read more about Optimizer Access Paths: index unique scan[…]

Optimizer Access Paths : Fast Full Scan

Posted on by sanjeeva

An index fast full scan reads the entire index as it is i.e. as it exists on the disk. This index read is unsorted. This access path usage multiblock IO to perform the index scan. Index fast full scan simply reads all of the leaf, branch and root block of index quickly using multiblock IO Read more about Optimizer Access Paths : Fast Full Scan[…]

Data Replication Setup Using Master and Slave: PostgreSQL- IV

Posted on by sanjeeva

This is last and final blog on Master-Slave replication in PostgreSQL database. In last blog, we have seen Async node setup. We are exploring Sync node in this blog. We will use the same automation script for Sync node also with two changes in master and one change in slave configuration. Let’s start with master. Read more about Data Replication Setup Using Master and Slave: PostgreSQL- IV[…]

Data Replication Setup Using Master and Slave: PostgreSQL- III

Posted on by sanjeeva

In last few blogs, we have seen how to automate steps required to setup Master-slave nodes. This blog would be the last in this series. Until now we have discussed how the architecture should look like and what parameters are needed to be modified to what value on master and slave node. In this blog, Read more about Data Replication Setup Using Master and Slave: PostgreSQL- III[…]

PostgreSQL Meta-Command using psql: Command Information -IV

Posted on by sanjeeva

This is in continuation of My last blog about Meta Commands in PostgreSQL. In last blog I have explained what a Meta command and how to list databases. In next few blogs we will explore few of Meta commands. Lets start exploring schemas. Visit this series of last blog for other command. The command we Read more about PostgreSQL Meta-Command using psql: Command Information -IV[…]

Data Replication Setup Using Master and Slave: PostgreSQL – I

Posted on by sanjeeva

In last few blogs, we have seen how to automate steps required to setup Master-slave nodes. In next few blogs we will explore how High Availability(HA) will be setup. In this blog we will talk about how the architecture look like. To achieve HA in the PostgreSQL database, we should setup a Master-Slave replication environment Read more about Data Replication Setup Using Master and Slave: PostgreSQL – I[…]

Data Replication Setup Using Master and Slave: PostgreSQL – II

Posted on by sanjeeva

In last few blogs, we have seen how to automate steps required to setup Master-slave nodes. In next few blogs we will explore how High Availability(HA) will be setup. We can implement this master-slave environment on separate VMs. We can also implement this on the same machine. For blogging purposes, we will use the same machine for Read more about Data Replication Setup Using Master and Slave: PostgreSQL – II[…]

Oracle Direct Path Read: Complete Performance Guide with Real Examples

Posted on by sanjeeva

Have you ever wondered why some of your Oracle queries bypass the buffer cache entirely and read data directly from disk? Recently, we encountered this exact scenario while investigating performance issues in a data warehouse environment, and I wanted to share our findings about Oracle’s direct path read mechanism. Oracle Direct Path Read is a Read more about Oracle Direct Path Read: Complete Performance Guide with Real Examples[…]

Optimizer Access Paths : What is Index Full Scan

Posted on by sanjeeva

Index full scan is the optimizer access path where the database reads the index from start to end, one block at a time. It reads the index starting from the root block, navigating down using branch towards the left side, or right side if we are doing a descending full scan until it hits the Read more about Optimizer Access Paths : What is Index Full Scan[…]

Automating Master and slave replication: PostgreSQL – I

Posted on by sanjeeva

Master-slave replication setup is the implementation of HA in PostgreSQL. Deployment architecture of 1 master and at least one slave in SYNC mode would be able to provide senses of High Availability of the database. To achieve this we require some steps to be performed into the database which will make one of the nodes Read more about Automating Master and slave replication: PostgreSQL – I[…]

MVCC Concurrency Architecture: PostgreSQL way of implementation – III( pros/cons)

Posted on by sanjeeva

We have explored the PostgreSQL implementation of MVCC in the last two blogs. We will understand the pros and cons of this way of implementation in this blog. This implementation avoided the need for locking of a tuple for any possible updates because the updates are not in-place. Updates in PostgreSQL are creating a complete Read more about MVCC Concurrency Architecture: PostgreSQL way of implementation – III( pros/cons)[…]

PostGIS Installation with PostgreSQL

Posted on by sanjeeva

PostgreSQL supports many other tools in form of database extensions like UUID support, dblink. In the same way, it also supports geographic and spatial data with help of PostGIS. This blog will explain how to install PostGIS 2.5 which can be used by PostgreSQL 11. There are many version of this spatial extension of database Read more about PostGIS Installation with PostgreSQL[…]

What is a Database Cluster: PostgreSQL

Posted on by sanjeeva

In the last blog, we have installed PostgreSQL on different Linux platforms ( CentOs, Ubuntu). However, We have leftover to initialize the installation and connection to the database that we will discuss here. Postgres provides more than one way to initialize a database cluster. We will use pg_createcluster in this blog. But before that, we Read more about What is a Database Cluster: PostgreSQL[…]

PostgreSQL Meta-Command using psql: Command Information -III

Posted on by sanjeeva

This is in continuation of My last blog about Meta Commands in PostgreSQL. In last blog I have explained what a Meta command and how to list databases. In next few blogs we will explore few of Meta commands. Lets start exploring schemas. Visit this series of last blog for other command. The command we Read more about PostgreSQL Meta-Command using psql: Command Information -III[…]

PostgreSQL Meta-Command using psql: Command Information -II

Posted on by sanjeeva

This is in continuation of My last blog about Meta Commands in PostgreSQL. In last blog I have explained what a Meta command is all about. In next few blogs we will explore few of Meta commands. Lets start exploring databases. The command we will explore here is:1. \l2. \c Once you connected to a Read more about PostgreSQL Meta-Command using psql: Command Information -II[…]

Optimizer Access Paths: How Index FFS works with Distinct

Posted on by sanjeeva

Distinct is the keyword that oracle used to filter out unique values from a column. However, it is very interesting to see the behavior followed by the optimizer for its access path. In this “Optimizer Access Paths” blog, we will see how we can make optimizer to use an index with a distinct keyword. Let’s Read more about Optimizer Access Paths: How Index FFS works with Distinct[…]

MVCC Concurrency Architecture: PostgreSQL way of implementation – II

Posted on by sanjeeva

This is in continuation from my last blog on PostgreSQL implementation of MVCC. We will understand transaction id (XID), versioning of a tuple (xmin & xmax) in more detail. Before we move to understand the implementation of a transaction using MVCC, let’s first understand how a tuple is created/updated/deleted. PostgreSQL assigns the current transaction id Read more about MVCC Concurrency Architecture: PostgreSQL way of implementation – II[…]

Optimizer Access Paths: How oracle database works

Posted on by sanjeeva

In this blog, we will explore what is the access path in the Oracle database. However, before moving to the access path, let’s first understand what is a row source. It is a set of rows that are returned in a step by execution plan. It can be a table or a result of join operations Read more about Optimizer Access Paths: How oracle database works[…]

Concurrency Control in PostgreSQL

Posted on by sanjeeva

In previous blog, we have detailed out about the inception of PostgreSQL. In this blog, we will explain the architecture (MVCC) with respect to PostgreSQL. Concurrency Control: There are more than one way to provide concurrency control by database. Concurrency is an important factor to allow many users to work on the same dataset at Read more about Concurrency Control in PostgreSQL[…]

PostgreSQL Meta-Command using psql: Command Information -I

Posted on by sanjeeva

This is in continuation of My last blog about Meta Commands in PostgreSQL. In last blog we have explained what a Meta command is all about. In next few blogs we will explore few of Meta commands. Let’s start with psql command itself. Once we logged in using psql, the environment should be look like Read more about PostgreSQL Meta-Command using psql: Command Information -I[…]

How To: List keys of collection MongoDB

Posted on by sanjeeva

There are many things needed in the DBA’s life for which there are no simple and straight forward ways to find out and they sometimes are tricky to find out. One of them is to find the keys of a collection. There are alternate methods we can certainly explore to retrieve all keys. the catch Read more about How To: List keys of collection MongoDB[…]

PostgreSQL Meta-Command using psql: Generic Information

Posted on by sanjeeva

In our last blog we have discussed the history of origination of PostgreSQL database. This database, like all other RDBMS, has more than one interface to connect to the database. PostgreSQL has psql program as command line interface (CLI) and PgAdmin as graphical user interface (GUI) psql as complete set of commands through which we Read more about PostgreSQL Meta-Command using psql: Generic Information[…]

PostgreSQL Installation on CentOS 7

Posted on by sanjeeva

There are multiple ways of installation of the PostgreSQL database on Unix like platforms. We will explore the installation of PostgreSQL version 12 on CentOS 7 using YUM installation. Let’s start. Verifying the version of CentOS: root@localhost yum.repos.d]# rpm -q centos-release centos-release-7-7.1908.0.el7.centos.x86_64 PostgreSQL allows us to download many version across multiple platform, one should visit its official Read more about PostgreSQL Installation on CentOS 7[…]

PostgreSQL Installation on Ubuntu

Posted on by sanjeeva

There are multiple ways of installation of the PostgreSQL database on Unix like platforms. We will explore the installation of PostgreSQL version 11 on Ubuntu 18.04 LTS using apt installation. Let’s start. Login to Ubuntu and check the version of Ubuntu. postgres@sanjeeva:/home/sanjeeva/postgres$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 18.04.5 LTS Release: Read more about PostgreSQL Installation on Ubuntu[…]

Evolvement of PostgreSQL: Background

Posted on by sanjeeva

Research papers of “System R” from IBM were initially picked up by two professors, Michael Stonebraker and Eugene Wong, at Berkeley University, California. This resulted in a new database called INteractive Graphics REtrieval System i.e. “Ingres“. The work done by this duo for Ingres becomes the foundation of many relational databases like MS SQL Server, Read more about Evolvement of PostgreSQL: Background[…]

How To: List all indexes in MongoDB

Posted on by sanjeeva

Indexes are a very important structure in any database and the same is true with MongoDB as well. It adds spices to the performance of your query. It is also very important to know what and how many indexes are created on your DB. In the normal life of DBA, one needs to find out Read more about How To: List all indexes in MongoDB[…]

How To: Creating a collection subset from collection in MongoDB

Posted on by sanjeeva

Many a time there are required to create a new collection from existing ones with the same or different size. In this blog, we will see how to create a new collection from the existing one and with a smaller size. For Sample data, We may use Kaggle to get huge data set. In my collection, I Read more about How To: Creating a collection subset from collection in MongoDB[…]

Cloud database war: Advantage shifting to Red?

Posted on by sanjeeva

With its inception in 2006, Amazon AWS has definitely gone a long way.  Engineers from Amazon worked really-really well which has not only completely changed the horizon of cloud but also emerges as one of the boon for any business to adopt.  Although, there are many other vendors available in the cloud market and they Read more about Cloud database war: Advantage shifting to Red?[…]

WiredTiger: A game changer for MongoDB

Posted on by sanjeeva

Storage engine is one of the key component of any database.  It is, in fact, a software module which is used by database management system to perform all storage related operations e.g. create information, read information and update any information.  The term storage means both disk storage and memory storage.   Choosing right storage engine is Read more about WiredTiger: A game changer for MongoDB[…]

Data Pump: impdp

Posted on by sanjeeva

Problem Statement: Restore entire database using Data Pump. Restore table(s) Restore tablespace(s) Restore schema(s) Restore using Transportable tablespaces (TTS) Restore from multiple small sizes of dump files Restore in parallel mode Approach: There are single shot solution to all the above problem statement and it is IMPDP in Data Pump.  It is one of various Read more about Data Pump: impdp[…]

Oracle Database Growth Trends: Complete DBA_HIST_SEG_STAT Analysis Guide

Posted on by sanjeeva

Have you ever needed to analyze Oracle database growth trends but found yourself limited by current snapshot data? In real production environments, tracking database growth trends is a critical aspect of DBA life because this allows businesses not only to foresee the real position in terms of existing hardware but also enables planning future expenses Read more about Oracle Database Growth Trends: Complete DBA_HIST_SEG_STAT Analysis Guide[…]

Oracle Data Pump: expdp & impdp

Posted on by sanjeeva

Problem Statement: Backup entire database using Data Pump. Backup table(s) Backup tablespace(s) Backup schema(s) Backup using Transportable tablespaces (TTS) Generate multiple small sizes of dump files Backup in parallel mode Approach: There are single shot solution to all the above problem statement and it is Data Pump.  It is one of various backup tools provided Read more about Oracle Data Pump: expdp & impdp[…]

Data Pump: a tool to backup and restore database

Posted on by sanjeeva

Among various techniques of backing up your database Oracle provides data pump as one of tool which they are constantly improving and making this tool sharper release by release. Since its first launch with 10g version, it has improved a lot not only in terms of its new features but in terms of performance as Read more about Data Pump: a tool to backup and restore database[…]

MongoDB Enterprise Edition Installation – Ubuntu

Posted on by sanjeeva

MongoDB is one of the document oriented open source database developed in c++, first come into shape in 2007 when in order to overcome the shortfall of existing database while working for an advertising company “DoubleClick” development team has decided to go further rather than struggling with database.  The team of this advertising company was Read more about MongoDB Enterprise Edition Installation – Ubuntu[…]

How to: Uninstallation of MongoDB on Ubuntu

Posted on by sanjeeva

MongoDB is one of the document oriented open source database developed in c++, first come into shape in 2007 when in order to overcome the shortfall of existing database while working for an advertising company “DoubleClick” development team has decided to go further rather than struggling with database.  The team of this advertising company was Read more about How to: Uninstallation of MongoDB on Ubuntu[…]

MongoDB Installation – Ubuntu

Posted on by sanjeeva

MongoDB is one of the document oriented open source database developed in c++, first come into shape in 2007 when in order to overcome the shortfall of existing database while working for an advertising company “DoubleClick” development team has decided to go further rather than struggling with database.  The team of this advertising company was Read more about MongoDB Installation – Ubuntu[…]

Mongo DB – An Introduction

Posted on by sanjeeva

About NoSQL:  Let’s understand about the NoSQL.  We will explore MongoDB and it’s inception later. Like any other type of database NoSQL database also provides a mechanism to store and retrieve which is modeled in such a way so that it should be different than Relational database.  In short, a NoSQL database does not store Read more about Mongo DB – An Introduction[…]

How to re-organize your data files of a tablespace

Posted on by sanjeeva

Problem statement:  How to move data files from one location to another on same storage. How to move data files from one storage to another. How to rename data files to make data file name standardized Environment / Scenario: You have a database where you have to move your data files from old slower storage Read more about How to re-organize your data files of a tablespace[…]

How to copy Multi terabyte data to another Database Server

Posted on by sanjeeva

Problem statement:  How to migrate huge data from One DB to another DB. Multi-Terabyte data loaded on one database should be copied to another database. Environment: You have multi-terabyte Database Your database is growing on daily basis, based on data feeds. Number of Indexes on these tables are very high, and thus, size of indexes Read more about How to copy Multi terabyte data to another Database Server[…]

Move DB with Oracle 11g Binaries

Posted on by sanjeeva

Problem Statement: Move DB with Oracle Binaries on New Storage Create new DEV/UAT from Production. Scenarios: While creating new UAT or DEV from production and make this version of oracle to the same patch set level as of production, there are more than to move DB with Oracle Binaries. Examples: One way to move DB Read more about Move DB with Oracle 11g Binaries[…]

How to: Speed up Inserts in database

Posted on by sanjeeva

We have written blogs which helps DBA doing their day to day works.  This blog will explain how to Speed up Inserts while loading data from huge files.  Problem Statement: The problem statement this blog is going to answers with respect to Speed up Inserts are: How to speed up loading millions of rows from Read more about How to: Speed up Inserts in database[…]

Reduce in MapReduce … Unwinding

Posted on by sanjeeva

In our previous blogs we have studied about Big data, Hadoop.  We have also explained MapReduce internal workings like how Map works using short and shuffle.  This blog is dedicated to Reduce in MapReduce. Once this shuffling completed, it is where Reduce in MapReduce come into action. Its task is to process the input provided Read more about Reduce in MapReduce … Unwinding[…]

MapReduce – Sort & Shuffle

Posted on by sanjeeva

This is in continuation of MapReduce Processing   We are going to see how the input is provided to SORT process, how this is sorted and distributed on all available DNs and this input is taken over to the next step Shuffle. This output will be input for next process which is SORT. Sort takes Read more about MapReduce – Sort & Shuffle[…]

MapReduce – Unwinding Map

Posted on by sanjeeva

In last discussion on MapReduce, we discussed the algorithm which is used by Hadoop for data processing using MapReduce. In this blog, we will discuss the specific section of MAP in MapReduce and it’s functionality. Unwinding Map We will explain this in details and with example here. Example: Lets consider our scenario : The Scenario: Read more about MapReduce – Unwinding Map[…]

MapReduce – Unwinding Algorithm

Posted on by sanjeeva

With discussion, in my last blog, about “How Hadoop manages Fault Tolerance” within its cluster while processing data, it is now time to discuss the algorithm which MapReduce uses. Name Node (NN) It is Name Node (NN) where a user submits his request to process data and submits his data files.   As soon as NN receives data Read more about MapReduce – Unwinding Algorithm[…]

MapReduce : Fault Tolerance

Posted on by sanjeeva

The Fault Tolerance: Before we see the intermediate data produced by the mapper, it would be quite interesting to see the fault tolerant aspects of Hadoop with respect to MapReduce processing. The Replication Factor: Once Name node (NN) received data files which has to be processed, it splits data files to assign it to Data Read more about MapReduce : Fault Tolerance[…]

MapReduce Internals: Philosophy

Posted on by sanjeeva

In our last few blogs we have explained what is BigData, How Hadoop evolved & MapReduce workings.  In this blog we will see the philosophy of MapReduce. The Philosophy: The philosophy of MapReduce internals workings is straight forward and can be summarized in 6 steps. The smaller, the better, the quicker: Whatever data we provide Read more about MapReduce Internals: Philosophy[…]

MapReduce : Internals

Posted on by sanjeeva

The MapReduce Framework: MapReduce is a programming paradigm that provides an interface for developers to map end-user requirements (any type of analysis on data) to code. This framework is one of the core components of Hadoop. The capabilities: The way it provides fault-tolerant and massive scalability across hundreds or thousands of servers in a cluster Read more about MapReduce : Internals[…]

HDFS Architecture : Explained

Posted on by sanjeeva

Inspired by Google’s GFS,
HDFS (Hadoop Distributed File System ) architecture has designed in such a way that it has excellent fault-tolerant and self-healing features. It enables Hadoop to harness the true capability of distributed processing techniques…..

Magic of Hadoop

Posted on by sanjeeva

Disadvantage of DWH: Because of the limitation of currently available Enterprise data warehousing tools, Organizations were not able to consolidate their data at one place to maintain faster data processing. Here comes the magic of hadoop for their rescue. Traditional ETL tools may take hours, days and sometimes even weeks.  And because of this, performances Read more about Magic of Hadoop[…]

Journey of Hadoop

Posted on by sanjeeva

History of Hadoop: At the outset of twenty-first century, somewhere 1999-2000, due to increasing popularity of XML and JAVA, internet was evolving faster than ever. This leads to the invention of Hadoop. Requirement is mother of invention: As the world wide web grew at dizzying pace, though current search engine technologies were working fine, a Read more about Journey of Hadoop[…]

Big Data: Introduction and 4V’s

Posted on by sanjeeva

Innovations in technologies made the resources cheaper than earlier.  This enables organizations to store more data at lower cost and thus increasing the size of data. Gradually the size of data becomes bigger and now it moves from Megabytes (MB) to Petabytes (1e+9 MB). This huge increase in data requires some different kind of processing.  Read more about Big Data: Introduction and 4V’s[…]