SSIS Conditional split results in deadlock error

Question

I have a conditional split in an SSIS job that inserts or updates based on the CDC operation. The deletes dont actually delete, they just mark the row deleted (so it is also an update statement).

This is what it looks like:

And the error message associated with the red x is

"Transaction (Process ID 67) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.".

I tried to put an additional input arrow in there, so it only runs one update at a time, but it won't let me.

Answer 1

I suspect FactWaybillTrans is has table lock checked in the destination. That's usually what you want when loading large amounts of data. However, since you also want to update the same thing, that is going to conflict with the lock and thus, you get a deadlock. Even without checking table lock, the default lock could escalate to a full lock.

I would look to stage my updates to a table ( stage.CDCWaybillUpdates ) and then have an Execute SQL Task fire after the Data Flow. Much cleaner and no opportunity for deadlocks.

You might be able to fake it but it'd be totally unreliable. Add a Sort Operation between the NumRowsUpdated and Update. That might be able to induce enough drag so that the OLE DB Destination finishes and releases its lock before the update begins firing. If it doesn't slow it down enough, then sort the same data in the opposite direction. Terrible, hackish approach but sometimes you have to do the dumb.