# ask-community

Matthew Karas

05/31/2023, 7:38 PM
Hi Dagster again - how are materialized assets generally set up for rerunning in the case of an error - do programmers have to set up their materialized assets to clear out a previous run of the asset materialization? Or is a second op/job type thing set up to do cleanup. What's the standard way of rerunning assets materializations that failed and added rows to the db?


06/01/2023, 6:05 PM
Hi Matthew. How I think about it is that the asset output is the source of truth for the current state of the asset. So re-materializing will overwrite the existing contents; assuming the input is the same, the overwrite will produce the same outputs as before. So for example, if an unpartitioned asset represents a table, re-materializing would rebuild the whole table. And if you wanted to update your table in chunks, you could represent your table as a partitioned asset where each chunk is a partition, so you can rebuild each chunk independently.

Matthew Karas

06/01/2023, 6:35 PM
Thanks Claire - I went forward with your general approach (overwrite rather than a command to back data out)