What are the write conflict scenarios in each isolation level when using row-level concurrency in Databricks?
In Databricks, write conflicts with row-level concurrency depend on the isolation level. Here's a summary of the write conflict scenarios in each isolation level when using row-level concurrency:

1. WriteSerializable:
   - INSERT operations do not conflict with any other write operations.
   - UPDATE, DELETE, and MERGE INTO operations can conflict when modifying the same row.
   - OPTIMIZE operations do not conflict with other write operations, except when ZORDER BY is used.

2. Serializable:
   - INSERT operations do not conflict with any other write operations.
   - UPDATE, DELETE, and MERGE INTO operations can conflict when modifying the same row.
   - OPTIMIZE operations do not conflict with other write operations, except when ZORDER BY is used.

In both isolation levels, tables with identity columns do not support concurrent transactions. Additionally, tables with partitions do not support row-level concurrency but can still avoid conflicts between OPTIMIZE and all other write operations when deletion vectors are enabled.