PeerDB’s Postgres connector can detect schema changes in the source tables. For Postgres, BigQuery and Snowflake destinations, it can propagate some of these changes to the corresponding destination tables as well. The way each schema change is handled is documented below:
| Schema Change Type | Behaviour |
|---|---|
Adding a new column (ALTER TABLE ADD COLUMN ...) | Propagated automatically once the table gets an insert/update/delete, all rows after the change will have all columns filled |
Adding a new column with a default value (ALTER TABLE ADD COLUMN ... DEFAULT ...) | Propagated automatically once the table gets an insert/update/delete, all rows after the change will have all columns filled but existing rows will not show the DEFAULT value without a full table refresh |
Dropping an existing column (ALTER TABLE DROP COLUMN ...) | Detected, but not propagated. All rows after the change will have NULL for the dropped columns |