Metadata
- Author: Dremio
- Full Title:: Row-Level Changes on the Lakehouse: Copy-on-Write vs. Merge-on-Read in Apache Iceberg
- Category:: 🗞️Articles
- URL:: https://www.dremio.com/blog/row-level-changes-on-the-lakehouse-copy-on-write-vs-merge-on-read-in-apache-iceberg/
- Finished date:: 2023-03-13
Highlights
With COW, when a change is made to delete or update a particular row or rows, the datafiles with those rows are duplicated, but the new version has the updated rows. This makes writes slower depending on how many data files must be re-written which can lead to concurrent writes having conflicts and potentially exceeding the number of reattempts and failing. If updating a large number of rows, COW is ideal. (View Highlight)