Oracle on Ivan Luminaria

Oracle on Linux: the kernel parameters nobody configures

Tue, 24 Feb 2026 08:03:00 +0100

The client was a logistics company running Oracle 19c Enterprise Edition on Oracle Linux 8. Sixty concurrent users, a custom ERP application, about 400 GB of data. The server was a Dell PowerEdge with 128 GB of RAM and 32 cores.

The complaints were vague but persistent: “The system is slow.” “Morning queries take twice as long as two months ago.” “Every now and then everything freezes for a few seconds.”

Ragged hierarchies: when the client has no parent and the group has no grandparent

Tue, 20 Jan 2026 08:03:00 +0100

Three levels. Top Group, Group, Client. It looks like a trivial structure — the kind of hierarchy you draw on a whiteboard in five minutes and that any BI tool should handle without issues.

Then you discover that not all clients belong to a group. And that not all groups belong to a top group. And that the aggregation reports the business asks for — revenue by top group, client count by group, drill-down from the top to the leaf — produce wrong or incomplete results because the hierarchy has holes.

4 million euros, two multinationals, zero software: the true story of a failure foretold

Tue, 30 Dec 2025 08:03:00 +0100

The story I’m about to tell is true. I won’t name names — not out of diplomacy, but because names don’t matter. What matters is understanding the mechanism. Because this mechanism repeats itself, identically, in dozens of companies. And it costs millions.

🏢 The client: an insurance group with a legitimate ambition #

A solid company in the insurance sector. Operations in Italy, France, Northern European countries, Spain. Thousands of employees, millions of policies under management, a growing business.