Posts Categorized: Technical Blog

Performance Problems with Dynamic Statistics in Oracle 12c

I’ve been making some tests recently with the new Oracle 12.1.0.2 In-Memory option and have been faced with an unexpected  performance problem.  Here is a test case: Waiting for in-memory segment population: Now let’s make a simple two table join: Query runs pretty fast. Execution plan has the brand new vector transformation After having such…

Troubleshooting a Multipath Issue

Multipathing allows to configure multiple paths from servers to storage arrays. It provides I/O failover and load balancing. Linux uses device mapper kernel framework to support multipathing. In this post I will explain the steps taken to troubleshoot a multipath issue. This should provide an glimpse into the tools and technology involved. Problem was reported…

Calculating Business Days in HiveQL

One of the common tasks in data processing is to calculate the number of days between two given dates. You can easily achieve this by using Hive DATEDIFF function. You can also get weekday number by using this more obscure function: SELECT FROM_UNIXTIME(your_date,’u’) FROM some_table; This will return 1 for Monday, 7 for Sunday and…

Merging Apps Patches in Oracle EBS R12.2

It’s public knowledge that the traditional patching tool in Oracle EBS “adpatch” is replaced with “adop” utility. It’s also known that adop utility automatically merges patches when more than one patch is specified in the command line arguments. So whats the need for blog post on merging patches when its taken care automatically? This blog…

Deploying a Private Cloud at Home — Part 7

Welcome to part 7, the final blog post in my series, Deploying Private Cloud at Home, where I will be sharing the scripts to configure controller and computer nodes. In my previous post, part six, I demonstrated how to configure the controller and compute nodes. Kindly update the script with the password you want and then execute. I am assuming…

Deploying a Private Cloud at Home — Part 6

Today’s blog post is part six of seven in a series dedicated to Deploying a Private Cloud at Home, where I will be demonstrating how to configure controller node with legacy networking ad OpenStack dashboard for webgui. Feel free to check out part five where we configured compute node with OpenStack services. First load the admin variables…

High System Time on Windows Running in a VM

Recently I’ve seen an issue with CPU usage on a server running Windows 2003 Server in a VMware. This is a small Virtual Machine with just 2 cores allocated (which are possibly mapped to “threads” on a host level but I don’t know the details). For some reason very high System CPU time was reported…

Deploying a Private Cloud at Home — Part 5

Today’s blog post is part five of seven in a series dedicated to Deploying Private Cloud at Home, where I will be demonstrating how to configure Compute node and OpenStack services on the compute node. We have already installed the MySQL Python library on compute node in previous posts. Install OpenStack compute packages on the node yum…

An Introduction to Extended Data Types in Oracle 12c

One of the lesser known new features that comes as a boon to many developers and DBAs is the provision of implicit handling of large data strings using scalar data types like VARCHAR2 and RAW. When creating tables, each column must be assigned a data type, which determines the nature of the values that can…

Debugging High CPU Usage Using Perf Tool and vmcore Analysis

There are several tools and technologies available to debug deeper into high CPU utilization in a system; perf, sysrq, oprofile, vmcore, and more. In this post, I will narrate the course of debugging a CPU utilization issue using technologies like perf and vmcore. Following sar output is from a system which faces high %system usage. [root@prod-smsgw1…

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