Support replication into pre-existing custom destination tables in ClickHouse without dropping or recreating them #3971
Description
We have already created custom destination tables in ClickHouseDB with our own schema, indexes, and configurations. When setting up a PeerDB mirror from MariaDB to ClickHouse, PeerDB throwing an error instead of reusing the existing one.
Expected Behavior:
- PeerDB should detect that the destination table already exists in ClickHouse.
- It should skip table creation entirely and reuse the existing table.
- All CDC changes (INSERTs, UPDATEs, DELETEs) from MariaDB should be applied Full or incrementally on top of the existing data in the destination table.
- PeerDB should never drop or recreate a destination table that already exists, unless explicitly instructed to do so via a flag/option.