“Failed to lock variable” SSIS error

Question

I am getting an error randomly for a scheduled SSIS package which runs hourly. The funniest thing is that if I delete the checkpoint file and run the package again it works

Answer 1

I'd suspect that this is related to the same variable being written to in multiple components that execute in parallel. Essentially this would be a race condition on that variable.

For example if Component A and Component B can execute in parallel and both write to a given variable then it is possible that Component A will be writing to it (rendering it unavailable) when Component B tries to execute. As the start time of the two jobs will vary between runs you can get cases where the package appears to fail randomly.

To resolve the issue you would need to either add an additional variable so that they are not shared or alternatively force one component to complete before the other begins (through a dependency).

Hope this helps.