Posts Categorized: Technical Blog

Monitoring Cassandra with Grafana and Influx DB

Grafana_cassandra-test2

Hello, In this post I will explain how to set up Cassandra monitoring with influxDB and Grafana. This can also be used to connect to other monitoring systems (Graphite, Collectd, etc…) but since both influxDB and Grafana are hot topics at the moment I decided to follow the trend! I was asked why I was…

Detecting Source of MySQL Queries with Comments

As a MySQL DBA I already know the data changes that happen on my system. I have logs for that. However, it’s a common problem that several years into the life of an application, the current developers won’t know where in the codebase queries come from. It’s often hard for them to find the location…

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…

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