SSIS data flow Lookup fails but destination component still wrote rows

I'm using SSIS on SQL Serv开发者_StackOverflower 2008. I have a data flow with a lookup component with the no matching entries option specified to "Fail component". I'm looking at the log of a previous execution of the package and I can see the following error message from the data flow:

Row yielded no match during lookup.  

Later error messages indicate this is from my lookup component. However after that I can see an information message (from the same data flow and the same execution) saying that the destination component wrote several thousand rows:

"component "OLE_DST ..." (578)" wrote 9924 rows.  

An execution on another environment resulted in the same "Row yielded no match during lookup" error but then wrote zero rows to the destination.

The SSIS package is exactly the same in both environments. The data was slightly different but had the same characteristics - source rows, a small number with no matching lookup entry.

Is this behaviour allowed? Can the data flow begin writing an arbitrary number of rows before a lookup fails and then stop writing rows?

Tom,

Yeah, this behaviour is plausible. However I think (best to check this) it can be affected by FastLoadMaxInsertCommitSize because that property determines how many rows are inserted before being committed.

Read more: Default value for OLE DB Destination FastLoadMaxInsertCommitSize in SQL Server 2008

cheers

JT