Hi there, I’m Kaushik, one of the co-founders of PeerDB. PeerDB doesn’t handle schema changes today.
For CDC, change stream does give us events in case of schema changes, we would have to replay them on the destination. Schema changes on the destination are not supported, the general recommendation is to build new tables / views and let PeerDB manage the destination table.
For streaming the results of a query, as long as the query itself can execute (say a few columns were added or untouched columns were edited) mirror job will continue to execute. In case this is not the case, there will be some manual intervention needed to account for the schema changes.
Thanks for the question, this is a requested feature and on our roadmap.
Calling out limitations like this in the documentation would go a long way in building confidence in the project. Better yet, if there's an example of how to deal with "day-2" operational concerns like this.
Simply looking at the docs on these two pages, its unclear to me whether there's a way to update the mirror definition when a schema change occurs or if I need to drop & recreate the mirror (and what the effects of this are in the destination):
Thanks for the feedback and I agree on making these missing features more visible in our documentation! We did it here - https://docs.peerdb.io/usecases/Real-time%20CDC/postgres-to-... But will make it more visible soon i.e. in streaming query, cdc, CREATE MIRROR docs etc. We were thinking something on the lines of ALTER MIRROR or provide a new OPTION in CREATE MIRROR that will automatically pick up schema changes etc. Exact spec is not yet finalized.
For CDC, change stream does give us events in case of schema changes, we would have to replay them on the destination. Schema changes on the destination are not supported, the general recommendation is to build new tables / views and let PeerDB manage the destination table.
For streaming the results of a query, as long as the query itself can execute (say a few columns were added or untouched columns were edited) mirror job will continue to execute. In case this is not the case, there will be some manual intervention needed to account for the schema changes.
Thanks for the question, this is a requested feature and on our roadmap.