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Oracle Deep Data Security in Oracle AI Database 26ai: End Users and Data Roles

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  Oracle AI Database 26ai answers this with a new feature called Oracle Deep Data Security , or “Deep Sec.” Deep Sec is a database-enforced authorization framework: instead of hoping application code, middleware, or an AI agent behaves correctly, you declare exactly which rows, columns, and even individual cells a given user, role, or application is allowed to touch — and the database enforces that rule on every single query, no matter who or what sent it. It works alongside familiar tools such as Oracle Label Security and Data Masking , but it introduces a cleaner, SQL-native way to define fine-grained access that scales far better than row-level security written in PL/SQL. The easiest way to understand Deep Sec is through three new building blocks that this article will use hands-on: ● Local End users — lightweight identities for application users that do not own schemas or objects, unlike traditional database users. ● Data roles — roles created specifically to carry fine-g...
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PostgreSQL vs Oracle: When Higher Cost Means Better Performance

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  Database optimizers don’t see the future. They make decisions based on statistics, estimates, and cost models — and most of the time, those decisions work remarkably well. But what if the optimizer says: “The Sequential Scan is cheaper.” …and reality says: “The Index Only Scan is almost twice as fast.” That is exactly what I wanted to investigate. For this experiment, I created a deliberately skewed PostgreSQL dataset containing 100 million rows , where almost every row has the same customer_type and only a single row represents a rare value. This creates the perfect environment to challenge the optimizer’s assumptions and compare estimated cost with actual execution time . The question is simple: Does PostgreSQL’s estimated cost really tell us which execution plan will be faster? The results were surprising. Not always. And the difference between what PostgreSQL estimated and what actually happened reveals an important lesson about reading and troubleshooting execution plan...
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