Andrej Pashchenko

There are various ways to recall the wonderful conferences of the past year during the slower pace of the Christmas season, such as this one. Who can guess this beautiful place? 🙂
Merry Christmas and hope to see you there next year!

Learning from mistakes is important. Better: learn from others' mistakes. Even better: today we can learn from @danischnider.bsky.social 's ones #doag2025

Fix Optimizer Estimate Issues from Implicit Conversions #JoelKallmanDay Learn how implicit RAW-to-VARCHAR2 conversions in Oracle break histograms, hurt optimizer estimates, and how to fix them safely.

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 @andrejsql.bsky.social shows how to improve row estimates with

Extended stats
Virtual columns

The long way of #JSON in #Oracle, from 12.1.0.2 until today. Now starting with 23ai and still 15 minutes left. Not bad!
You can do it!
#HrOUG2025 #HrOUG25

Tennis before the first session on day 3 of HrOUG with team „Awesome“ and „OMG“. It was great fun. Thanks! #HrOUG25 #HrOUG2025

Simplicity, Troubleshooting, #JoelKallmanday TL;DR: You don't have to be a genius to solve problems. And there is no shame in not-knowing or not understanding all the geeky details. Ma...

#joelkallmanday
We tend to forget that troubleshooting is mainly just about Clear and Calm thinking..
pdvfirstblog.blogspot.com/2025/10/simp...

New blogpost enesi.no/2025/10/uuid... #JoelKallmanDay #oracle

Fix Optimizer Estimate Issues from Implicit Conversions #JoelKallmanDay Learn how implicit RAW-to-VARCHAR2 conversions in Oracle break histograms, hurt optimizer estimates, and how to fix them safely.

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-optim...

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

How do I get the test data these days? My #Accenture colleague @cgohmannde.bsky.social explains. #makeit2025

Who will win? @andreakennel.bsky.social , @danischnider.bsky.social or #ChatGPT? We'll see.

I finish the first day of #MakeIT2025 like I started it: with a session of @andrejsql.bsky.social. This time he talks about parameterized views in Oracle

How can we help the Oracle optimizer to do better with function calls? @danischnider.bsky.social explains. #makeit2025

After the keynote at #MakeITConf, my Accenture colleague @andrejsql.bsky.social shared some interesting insights of table merging.

@oracleace.bsky.social

Conferences are always a chance to see my former colleagues of Trivadis again:

@andrejsql.bsky.social talking about table merging at #MakeIT2025

MERGE and DML RETURNING clause in Oracle 23ai Oracle 23ai finally supports MERGE … RETURNING! A long-awaited feature, but still hard to find in the docs.

MERGE ... RETURNING is now supported in Oracle 23ai.
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 go as far as inventing error codes). Read more:
#Oracle23ai #SQL #MERGE #OracleDB
blog.sqlora.com/en/merge-and...

ORA-30926 in Oracle 23ai: What’s Changed? Explore how Oracle 23ai improves MERGE behavior and error handling, replacing vague ORA-30926 message with clearer, smarter diagnostics.

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.bsky.social

blog.sqlora.com/en/ora-30926...

Thank you! It is hard to calculate as I didn't start from zero. At least it took the time to watch the videos on mylearn.

Oracle AI Vector Search Certified Professional he Oracle AI Vector Search Professional Certification is designed for Oracle DBAs, AI engineers, and cloud developers to unlock the potential of Oracle Database 23ai to build AI-driven applications. T...

Happy to share my new Oracle Certified AI Vector Search Professional certification! BTW, it is free until May 15 2025 #Oraclecertified #ConvergedDatabase
catalog-education.oracle.com/pls/certview...

When Compression Expands: The Hidden Pitfalls of HCC This post explores the behavior of Hybrid Columnar Compression (HCC) in Oracle Exadata while refreshing materialized views with atomic_refresh=true.

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.bsky.social
blog.sqlora.com/en/when-comp...

The same topic, the same @danischnider.bsky.social, but something has changed, the stage dimension perhaps? Note: stage dimension is not a new term in data warehousing, Dani is speaking about 😃

Excited to speak at #UKOUGDiscover24!
Do you also believe that collecting statistics in a data warehouse is not a ‘one size fits all’ approach? And that a targeted approach is part of your role as a data engineer?
Join my session on 2 December at 16:00. See you there!
ukoug.org/page/UKOUGCo...

@danischnider.bsky.social explains the performance of views on the big stage of the #DOAG2024

Mentioned you, your blog und linked to your package SQM_UTIL, @stewashton.bsky.social. Such package is a must have if you consider using SQL Macros. Thank you.

The wait is over: #DOAG2024 starts tomorrow in Nuremberg.
Want to learn about some advanced techniques and concepts around the practical use cases of #SQLMacros in #oracledatabase? Join me in the very first slot at 8:30