chunk() missed half of the mailing list

In a recent Habr article, the author analyzes a critical issue with the chunk() method when processing large datasets in background tasks. Using a project with 300,000 users as a case study, it was discovered that using chunk() with OFFSET causes records to be skipped because the selection window shifts after each iteration. Consequently, the bot sent messages to only half of the intended audience, while logs remained clean and metrics appeared normal. The author details the root causes of this error, discusses the limitations of the default withoutOverlapping() method, and proposes alternative approaches for implementing mass mailings. The article also covers optimizing composite database indexes to prevent duplicates and improve background process performance. This analysis is highly relevant for developers working with large datasets in Laravel or similar frameworks.