Andrej Pashchenko 🇺🇦 💙💛

📣 HrOUG & JavaCro 2026 Call for Speakers is open! Submit your talk or workshop and share your experience with the IT community. 🗓 Mar 1 – May 31, 2026 📍 Rovinj, Croatia 🔗 HrOUG: 2026.hroug.hr/eng/Call-for-p… 🔗 JavaCro: 2026.javacro.hr/eng/Call-for-S… #Java #Oracle #TechCommunity

New short blog series on Oracle 26ai CALENDAR functions. Part 2: execution context and the question — Do I still need a time dimension? #Oracle #SQL #26ai #DataWarehouse blog.sqlora.com/en/calendar-fu…

New short blog series on Oracle 26ai CALENDAR functions. Part 1: semantics and implementation nuances. #Oracle #SQL #26ai blog.sqlora.com/en/calendar-fu…

Storing UUIDs as RAW values is more efficient than strings But RAW can lead to implicit conversions => poor row estimates If you're stuck with string comparisons @Andrej_SQL shows how to improve row estimates with Extended stats Virtual columns blog.sqlora.com/en/fix-optimiz…

New post for #JoelKallmanDay! Ever wondered why the Oracle Optimizer sometimes ignores your histograms? Implicit data type conversions might be to blame. Here’s how to fix it without touching your SQL and with minimal schema impact. #Oracledatabase blog.sqlora.com/en/fix-optimiz…

Honored to speak at #HROUG2025 – celebrating its 30th anniversary in amazing Rovinj!🎉Huge thanks to the organizers for keeping this fantastic community going for 30 years!🙏 Let’s put some old SQL myths to the test together! #Oracle #SQL #Optimizer #Accenture #OracleAce

@MartinDBA @oracleace Yes, but the focus in New Features docs has shifted to old/new enhancements, almost ignoring that RETURNING was not available for MERGE before 23ai. At least in my perception.

@Andrej_SQL @oracleace The entire family of `returning into` clauses has been enhanced in Oracle Database 23ai. You get old and new values for insert, update and delete in addition to merge.

MERGE ... RETURNING is now supported in #Oracle23ai. In my view, it deserves more visibility in the documentation — it wasn’t easy to find. Even LLMs still claim it doesn’t exist (some even invent error codes). #SQL #MERGE @oracleace blog.sqlora.com/en/merge-and-d…

Ten years after my first post on the quirks of MERGE and ORA-30926, I took a fresh look at how Oracle 23ai handles it. Clearer error messages, improved diagnostics, and fewer unnecessary restarts. Read the new blog post #Oracle23ai #SQL #MERGE @oracleace blog.sqlora.com/en/ora-30926-i…

Did you know that refreshing HCC-compressed materialized views with atomic_refresh=true can multiply storage usage over time? Small details can have massive impacts. Read the new blog post. #Exadata #Oracle #HCC @oracleace blog.sqlora.com/en/when-compre…

Get rows in one table with no match in another with either c1 NOT IN ( SELECT c2 ... ) NOT EXISTS ( SELECT ... where c1 = c2 ) These perform the same in Oracle #SQL ...unless C2 includes NULL values => NOT IN returns no rows! @Andrej_SQL explores blog.sqlora.com/en/not-in-vs-n…

My @AccentureDACH colleague @Andrej_SQL is going to talk about partition exhange at the @Hroug_Croatia #HROUG2024 conference @oracleace

Partition Exchange Reloaded by @Andrej_SQL at #hroug2024.

Everything you should know about block corruptions in #Oracledatabase with @CGohmannDE at #hroug2024

@dani_schnider talking about the intelligence of #SQL Analysis report in #Oracle23ai at #hroug2024 in Rovinj @oracleace

On this #JoelKallmanDay, I would like to follow up on my last year's post, comparing #SQL’s NOT IN and NOT EXISTS, focusing on their usage, interchangeability and some myths about performance differences. blog.sqlora.com/en/not-in-vs-n… #Oracledatabase

And if you want to use your existing views and let SQL macros "inject" parameter, you can check the second part (blog.sqlora.com/en/parameteriz…) of this post and also @StewAshton 's post: stewashton.wordpress.com/2024/04/24/sql…

I am absolutely thrilled to be presenting at the #HROUG2024 for the first time. Thanks @Hroug_Croatia for accepting my talks. In just two weeks! See you there! @oracleace

There have been some changes and improvements to the Online Statistics Gathering for Bulk Loads over the last few years. Here is the new blog post: #oracledatabase @oracleace blog.sqlora.com/en/online-stat…

@CGohmannDE @odtug @oracleace @Accenture Congrats Christian! Well deserved!

Wow, what a great start to the day. I received the "ODTUG Kscope24 Engineering Top Speaker" award (lnkd.in/ekKF5Khd). Thank you @odtug and all the participants of my two presentations who filled out the evaluation forms. @oracleace @Accenture