Waldemar Scigajlo, PL/SQL Tuning Developer in Wrocław, Poland
Waldemar Scigajlo

PL/SQL Tuning Developer in Wrocław, Poland

Member since June 18, 2020
Waldemar is a back-end software developer. His expertise lies in the development of databases, focusing mainly on Oracle technologies, and third-party tools such as Java and Groovy. Waldemar also specializes in the creation of ETL processes with variable technologies like TOS, integration technologies, and Informatica.
Waldemar is now available for hire


  • BCG
    Groovy, Groovy Scripting, Git, GitHub, JavaScript, HTML, REST, Jira...
  • Revo
    Java, ETL, MySQL, Apache Superset, Talend ETL, ETL Development...
  • eConsulting
    Oracle, Java, Groovy, Virtualization, JBoss, ETL Development, LDAP, ETL...



Wrocław, Poland



Preferred Environment

Groovy, IntelliJ, Java, Oracle, Linux, Windows, Jira

The most amazing...

...software I've developed visualized the results of multi-dimensional mathematical functions, and their first and second derivatives.


  • Atlassian Jira Developer

    2020 - PRESENT
    • Prepared Jira workflows with customized screens and background Ajax functionality (behaviors, post scripting, and more.).
    • Tuned Jira screens using HTML and JavaScript manipulation, creating non-standard solutions like autosave, customer-side form validation, custom buttons for workflow maintenance, REST API calls via JavaScript for additional data retrieval, and more.
    • Performed Jira administration, user maintenance, problem analysis and solving, and Jira user support.
    • Created a Jira plugin for automating setup and maintenance of workflow, screens, behaviors, and back-end code.
    Technologies: Groovy, Groovy Scripting, Git, GitHub, JavaScript, HTML, REST, Jira, Jira REST API, Atlassian SDK, Adaptavist ScriptRunner, Atlassian Plugins, Jira Administration, Confluence
  • ETL and Database Developer

    2018 - PRESENT
    • Designed and developed a data warehouse based on MySQL database engine for reporting purposes.
    • Prepared ETL processes using Talend Open Studio for Big Data for various tasks, like merging data from other company databases and a MongoDB database.
    • Prepared the ETL process to provide reporting files accordingly to government specifications.
    Technologies: Java, ETL, MySQL, Apache Superset, Talend ETL, ETL Development, Data Warehouse Design, Data Warehousing
  • Data Virtualization Developer

    2016 - 2020
    • Designed and developed virtual databases using the JBoss Data Virtualization environment. Maintained groovy scripts responsible for data processing. Developed over 20 virtual databases for various business areas.
    • Developed a test automation tool for writing automated tests against databases using XML structures based on Groovy language, which helped to hold better data quality.
    • Maintained the team's workload, leading daily meetings.
    Technologies: Oracle, Java, Groovy, Virtualization, JBoss, ETL Development, LDAP, ETL, Business Intelligence (BI), Data Warehousing
  • Data Warehouse/ETL Developer

    2015 - 2016
    SMT Software
    • Designed and developed Informatica ETL processes to load big data sets.
    • Developed SQL Server stored procedures to process report data.
    • Designed and developed a Java desktop application for automating process generation.
    Technologies: Microsoft SQL Server, Informatica PowerCenter, Oracle, ETL Development, Python, ETL, Data Warehousing
  • Oracle Developer

    2014 - 2015
    SMT Software
    • Designed and developed Oracle databases using SQL and PL/SQL.
    • Created and maintained the data importing processes using shell scripting and SQL Loader.
    • Supported the Java and .NET development teams in solving data layer problems.
    • Adjusted database development processes by introducing automated deployment methods and database versioning.
    • Optimized the database and data processing to decrease processing time.
    Technologies: Shell, Unix, Windows PowerShell, PL/SQL, SQL, Database Design, Bamboo
  • Database Specialist

    2013 - 2014
    • Developed part of the core system as the database expert. Supported the database development via code reviews, performance monitoring, analyzing of problems, and proposing solutions.
    • Developed applications for database upgrades and installations.
    • Developed the load tests monitoring methodology using SSIS.
    • Organized the teamwork around the database and development of database upgrade script generators.
    • Prepared the migration from SQL Server 2005 to SQL Server 2012.
    Technologies: Reporting, Integration, C#, SQL, Database Schema Design, Database Design
  • Full-stack Developer

    2012 - 2013
    Lineas GmbH
    • Oversaw web development for both stationary and mobile browsers.
    • Oversaw server-side development. Main responsibilities included code development using Groovy and Cucumber and unit and automated integration tests.
    • Developed the database and data integration layer.
    • Participated in every part of the development process.
    Technologies: Hibernate, PostgreSQL, Microsoft SQL Server, Ajax, JSON, CSS, HTML, Selenium, GEB, JavaScript, Sencha Touch, Groovy, TeamCity
  • Database Developer

    2010 - 2011
    • Participated in the development of the data warehouse.
    • Developed ETL processes written in PL/SQL and SQL Loader.
    • Extended a small application built with Apex by adding new data views.
    • Created ETL process models using SAP Sybase PowerDesigner.
    Technologies: SQL Loader, Sybase PowerDesigner, Apex, PL/SQL, Oracle, ETL
  • Software Tester

    2008 - 2010
    Yumasoft Sp. z o.o
    • Performed manual tests of German banking software.
    • Analyzed system functionality in comparison to database content.
    • Tested changes and created documentation regarding found errors.
    Technologies: Oracle, Java, Manual Testing


  • Test Automation Tool for Database Systems Based on TAP

    This test automation tool was written using Groovy. It uses XML as the input files, along with the definition of tests and predefined assertions, such as comparing counts of rows, whole query sets, or database structures. It executes the assertions simultaneously, reusing connections and returned data sets for better performance, not holding entire data sets in its memory. The tool is platform-independent and extendable. Users may write their own assertion, compile them, or simply add it to an existing set of assertions by adding a jar file. It may connect to any database using the JDBC protocol, where the driver may also be added to the existing driver set without recompiling.

  • ETL Jobs for Importing Data into a Data Warehouse and Extract into a File

    The creation of ETL jobs for importing data into a MySQL database used Talend Open Studio for data integration (TOS), with a calling web service for data refresh and validation using Java. The project included the creation of a data extraction mechanism into a flat-file accordingly to the Polish credit office information system (BIK) format.

  • Automated Generation of Informatica ETL Job Definitions

    While preparing ETL jobs, I discovered that the specifications delivered by businesses are in a constant, predictable format (.docx document). Based on such documents, we were about to prepare ETL job definitions using the Informatica PowerCenter tool. I created a Java program that took the input file and automatically generated a job definition in Informatica XML format, which was easily consumed by the PowerCenter tool. The outcome of that process was that we managed to shorten the process creation from three-four weeks down to a few hours since we eliminated human errors while defining the jobs, such as typos and missed clicks. The tool also provided basic definition validation that allowed one to find documentation bugs in generation time.


  • Languages

    SQL, Groovy, Java, HTML, Hibernate Query Language (HQL), Apex, T-SQL, Java 8, C#, JavaScript, CSS, XML, Python
  • Paradigms

    Database Design, Testing, ETL, Manual Testing, Business Intelligence (BI), REST
  • Platforms

    Oracle, Windows, Linux, JBoss, Unix, Salesforce
  • Storage

    PL/SQL, PL/SQL Developer, Database Modeling, SQL Server 2012, SQL Server 2005, SQL Server Integration Services (SSIS), SQL Loader, JSON, Microsoft SQL Server, PostgreSQL, SQL Server 2008, MySQL, SQL Server Reporting Services (SSRS), MongoDB
  • Other

    PL/SQL Tuning, Data Virtualization, Database Schema Design, Query Optimization, Groovy Scripting, Design, Shell Scripting, Data Engineering, Data Warehouse Design, Atlassian Plugins, Data Modeling, Data Warehousing, Ajax, Integration, Reporting, Virtualization, Wikis, Multidimensional Expressions (MDX), LDAP, DW, Apache Superset, Adaptavist ScriptRunner, Jira Administration, ETL Development, Multithreading
  • Libraries/APIs

    Apache POI, Jira REST API
  • Tools

    IntelliJ IDEA, Eclipse IDE, Git, Subversion (SVN), Stash, Maven, Talend ETL, Jira, Atlassian SDK, Confluence, IntelliJ, Sybase PowerDesigner, Shell, Informatica PowerCenter, Visual Studio, Toad, Tableau, TeamCity, Bamboo, GitHub, Informatica ETL
  • Frameworks

    Sencha Touch, GEB, Selenium, Hibernate, Windows PowerShell, Ext JS, NHibernate


  • Master of Engineering Degree in Software Engineering
    2005 - 2011
    Wrocław University of Technology - Wrocław, Poland


  • Oracle PL/SQL Developer Certified Associate
    MAY 2015 - PRESENT
    Oracle University
  • Oracle SQL Certified Expert
    MAY 2015 - PRESENT
    Oracle University
  • Zertifikat Deutsch
    JUNE 2010 - PRESENT
  • ISTQB Certified Tester Foundation Level
    MAY 2010 - PRESENT

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