Summary A Python script using MariaDB began failing with DatabaseError(1020, “Record has changed since last read in table ‘db_control'”) after an upgrade to MariaDB 11.8.3 on Raspberry Pi OS Trixie. The root cause was identified as the default enabling of innodb_snapshot_isolation in this MariaDB version. This change alters how transaction isolation handles concurrent modifications, causing … Read more
Summary The issue at hand is displaying JavaScript output to an HTML page. The user has a JavaScript function that performs a math computation and wants to visualize the result on the front page when a button is pressed. However, the output is either undefined or nothing shows up. Root Cause The root cause of … Read more
Summary This postmortem addresses the architectural decisions and technical missteps involved in removing the default Windows title bar for a C++ WebView2 application. The core issue stems from attempting to mimic modern application aesthetics (like Notion) without accounting for the loss of native window management behaviors—specifically resizing, dragging, and window state management. The goal was … Read more
Summary This article explains the technical validation flow for API key authentication, using the OpenAI API as a concrete example. It covers how the server verifies the key, the backend middleware sequence, the difference between API keys and OAuth tokens, and common pitfalls. Root Cause The root cause of authentication failures lies in incorrect key … Read more
Summary The transition from bare-metal programming and RTOS-based systems to Embedded Linux can be challenging due to the complexity and size of the ecosystem. Key concepts such as handling peripherals, writing kernel drivers, and modifying the device tree are crucial for a successful transition. A recommended approach involves understanding the architectural boundaries and best practices … Read more
Summary The user attempted to use Response.Redirect in ASP.NET to initiate a file download, but the code failed to display the download dialog because Response.Redirect issues an HTTP 302 redirect, which interrupts the current response and navigates the client browser to a new URL. In ASP.NET, Response.Redirect also triggers Response.End() implicitly, which terminates the execution … Read more
Summary A developer building a CICS/DB2 application in COBOL encountered program length issues and compilation failures when attempting to modularize code using copybooks. The core issue stems from a misunderstanding of the precompilation order of operations. Because DB2 SQL (via EXEC SQL) must be preprocessed into standard COBOL before the COBOL compiler can process it, … Read more
Summary The problem at hand is creating a foreign key in a PostgreSQL database that references a sequence, rather than a table’s primary key. This is necessary to group repeating events in an event table without creating a separate table for event batches. The goal is to enforce a foreign key constraint strictly in reference … Read more
Summary The find() and filter() array methods in JavaScript serve different purposes for retrieving elements based on conditions. The key distinction is that find() returns the first matching element, while filter() returns an array of all matching elements. For the specific query regarding ID lookup in a small product array, both methods work, but find() … Read more
Summary We investigated the performance and readability differences between using flatMap() and a forEach() loop with concat() to flatten an array of objects. The core issue is that while both methods achieve the same result, flatMap() is significantly more performant and idiomatic for this specific use case. The forEach() approach creates intermediate arrays and iterates … Read more