Application Insights, structured logging, SQL query plans, ILogger, BenchmarkDotNet, pagination vs full-table fetch, memory dumps Production bugs and performance problems are different from development bugs. You cannot attach a debugger. You have limited visibility. The system is under real load. And in many cases, the issue is not an exception — it's slow code, a memory leak, or a database query that works fine with 100 rows but falls apart with 4 million. Part 1: Debugging Production Issues Structured Logging — Your First Line of Defence Production debugging starts and ends with good logs. // ❌ Bad — unstructured, unsearchable _logger . LogInformation ( "User " + userId + " placed order " + orderId ); // ✅ Good — structured, queryable _logger . LogInformation ( "User {UserId} placed order {OrderId} for {Product}" , userId , orderId , product ); Enter fullscreen mode Exit fullscreen mode Structured logging lets you query logs by field values in Application Insights, Seq, Datadog, or any log aggregator.…