05. 06. 2021.

Missing columns in PrestoSQL

One of the first issues when starting to use PrestoSQL distributed query engine is related to missing columns of certain data types, especially numeric and all variants of date. This issue is usually because of missing precision at the data source, which is not only one of the most common, but also one of the […]

01. 04. 2021.

Trino (ex. Presto) – troubleshooting distributed transactions among various data sources

In this post I’ll demonstrate one of many use cases of Presto technology, that you might overlooked – How to troubleshoot distributed transactions which are very common these days as a result of a complex Microservices architecture. In the following SELECT statement I’ll combine three different data sources: Oracle Postgres Kafka by using good old […]

17. 03. 2021.

Trino (ex. Presto) – high performance distributed query engine

In this article I’ll share some of my experiences with Trino (ex. Presto) – high performance distributed query engine.   First some intro about the project Presto. Couple of members from the Facebook infrastructure team created the project Presto to address problems they have with 300 Petabytes Hadoop Data Warehouse. The main goal of the […]

16. 02. 2021.

Postgres monitoring with Percona PMM

For those who are coming from Oracle world, the best alternative database is probably Postgres, because of many similarities between those two Db engines (data types, tablespace concept etc.).   However, one of the first thing you want to do is to grab a full control over what is going on in your database. If […]

06. 12. 2020.

Bashtop – future of the terminal Linux monitoring

Although the idea of the original top utility is follewed in many similar utilities for terminal based Linux monitoring, till now I’ve been using Htop, atop (which can monitor GPU on top of CPU/Mem/Net/Disk) and Nmon to do a job (later one, called „Topas on steroids” is ported from AIX to Linux). Quite recently I’ve […]

22. 07. 2019.

Oracle database benchmarking by using CALIBRATE_IO

CALIBRATE_IO is yet another popular database simulation/stress test utility, mainly used to perform IO benchmarks.   Procedure, that is part of DBMS_RESOURCE_MANAGER package, will generate read-only workload made up of 1 MB of random of I/Os to the database to determine the maximum number of IOPS and MB per second. You can save the following […]

07. 07. 2019.

bash history search on steroids

Today there are several hundreds (maybe even thousands) programming languages around (not to mention Domain Specific languages), but bash, with all its shortcoming, is still native language of all *nix servers around. With today’s choices you might not want to create scripts in bash, for one liners bash is still in. In this article I […]

01. 03. 2019.

Starting with Oracle Unit Testing Framework – Part 3 Automation

In this article I’ll describe how you can automate previously created Unit Test. I believe that many of the Oracle SQL Developer users use only core functionality of the tool, and have never become familiar with its more advanced features. I’ve already describes in several articles some of its advanced features (you can use search […]

28. 02. 2019.

Starting with the Oracle Unit Testing Framework – Part 2

This is a second part of the Oracle Unit Testing Framework post. In the first part I’ve created Unit Test repository and prepare everything for testing. Details you can find on the following link: https://www.josip-pojatina.com/en/starting-with-oracle-unit-testing-framework-part-1/   In this part I’ll perform actual test and show some of the numerous options that you have on disposal. […]

26. 02. 2019.

Impact of the JVM Garbage Collector on the realistic workload

At the last regional Java and Open Source conference where I held the presentation named: “Java Mission Control now in OpenJDK – best practice”, several questions have been raised about a way of testing JEE apps, influence of a GC (Garbage Collector) on the overall performance, new GC engines etc. With OpenJDK 11 we have […]