Hi James,
We don't hold locks on tables during DDL operations (other than for the one
operation that updates the system catalog with the new mutations). Adding a
column does not require any additional data-related operations as existing
rows will simply return null for the column. For deletion of
Is there any documentation anywhere to say what schema changes can be performed
online (without write-locking a whole table)?
For instance (but not exclusively): adding or deleting a column on a large
table.
James
Elsevier Limited. Registered Office: The
