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Optimistic Concurrency Control
DuckDB uses [optimistic concurrency control](https://en.wikipedia.org/wiki/Optimistic_concurrency_control), an approach generally considered to be the best fit for read-intensive analytical database systems as it speeds up read query processing. As a result any transactions that modify the same rows at the same time will cause a transaction conflict error:  
```console
Transaction conflict: cannot update a table that has been altered!
```  
> **Tip.  ** A common workaround when a transaction conflict is encountered is to rerun the transaction.