Andrej_SQL's profile picture. Database developer, data engineer, Oracle Ace Pro ♠
Born in Ukraine
Views are my own

Andrej Pashchenko 🇺🇦 💙💛

@Andrej_SQL

Database developer, data engineer, Oracle Ace Pro ♠ Born in Ukraine Views are my own

Andrej Pashchenko 🇺🇦 💙💛 أعاد

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

Andrej_SQL's tweet image. 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

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…


Andrej Pashchenko 🇺🇦 💙💛 أعاد

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…

sqldaily's tweet image. 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…

Andrej Pashchenko 🇺🇦 💙💛 أعاد

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

CGohmannDE's tweet image. My @AccentureDACH colleague @Andrej_SQL is going to talk about partition exhange at the @Hroug_Croatia #HROUG2024 conference

@oracleace

Andrej Pashchenko 🇺🇦 💙💛 أعاد

Partition Exchange Reloaded by @Andrej_SQL at #hroug2024.

phsalvisberg's tweet image. Partition Exchange Reloaded by @Andrej_SQL at #hroug2024.

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…

Views are great for creating reusable #SQL statements But they have a drawback: you can't pass parameters to them! @Andrej_SQ shows how to emulate these with SQL macros in Oracle Database Use these to create parameterized query templates blog.sqlora.com/en/parameteriz…

sqldaily's tweet image. Views are great for creating reusable #SQL statements

But they have a drawback: you can't pass parameters to them!

@Andrej_SQ shows how to emulate these with SQL macros in Oracle Database

Use these to create parameterized query templates

blog.sqlora.com/en/parameteriz…


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

Andrej_SQL's tweet image. 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
Andrej_SQL's tweet image. 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…


Andrej Pashchenko 🇺🇦 💙💛 أعاد

Join AOUG Anwenderkonferenz 2024 next week for many great sessions presented by Oracle ACEs 👉 @alexnuijten @Ambili_Thots @Andrej_SQL @JrgDoppelreiter @martinberger_ch @Mirela_RoOUG @RoelH @rsantrod @oraclesean @stefanoehrli social.ora.cl/60105VSQq #OracleACE

oracleace's tweet image. Join AOUG Anwenderkonferenz 2024 next week for many great sessions presented by Oracle ACEs 👉 
@alexnuijten @Ambili_Thots @Andrej_SQL @JrgDoppelreiter @martinberger_ch @Mirela_RoOUG @RoelH @rsantrod @oraclesean @stefanoehrli

social.ora.cl/60105VSQq
#OracleACE

As a data engineer, do I have to worry about optimizer statistics? In the second part is a typical example of why the performance immediately after loading the data can be suboptimal if you don't take care of the stats. #oracledatabase @oracleace blog.sqlora.com/en/object-stat…


I will talk about optimizer statistics at #AOUG Conference on June 17th, in particular what my responsibilities as a data engineer are. I think it's very important that it's not seen as just a DBA's job. Here is just one simple example of why: blog.sqlora.com/en/object-stat… @oracleace


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