Mariusz Krzanowski blog

Tag: bug

Azure Functions V3 and disappearing function.json files

Introduction

When I started migration process to Azure Function 3.0 of an existing project, I have discovered small, but painful inconvenience. The problem was that all function.json files were permanently removed from output folder just before Azure Function Tools func.exe was started. I have to confess it was very annoying. There were suggestions e.g. on StackOverflow or other sites to run PowerShell which copies files later – after emulator is started, but it was not a solution I like.

When aborted equals committed

The traditional SQL databases are used by developers as a fully safe storage. The ACID properties are intuitive for us and give us a sense of safety during application development. We know that if during a database transaction a network error occurred and we received an exception, the whole transaction would be rolled back as atomic part of process. To avoid network issues we can retry the operation later and it should solve the problem. It is true in most cases, but there is one when it is not so easy. Let me drill down this subject.

World without DTC

Distributed Transaction Coordination is sometimes slow, but guarantees the system consistency. You do not need to care about infrastructure things. I will describe a problem that appears when you have no DTC and you have two independent databases.

SQL – always sort by unique key to guarantee correct paging

SQL query engine is prepared to return correct results as soon as possible. But correctness means being correct from mathematical perspective. Problem that I will describe is obvious, but it is not what you sometimes expect from SQL engine.

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