Data engineering·Moving data out of the source
you tail the database's own replication log, so a delete and a mid-second update both come through without the source running a single extra query.
Log-based CDC
Also calledbinlog CDC, WAL-based capture, log tailing
Capturing changes by reading the database's write-ahead or binary log, the same feed a replica consumes. Because the log is the truth of what happened, you get every intermediate state, hard deletes and ordering for free, and you put no query load on the source. The price is operational: it needs a privileged connection, it is coupled to the source's storage engine and version, and if your consumer is down long enough for the log to be rotated away, recovery means a new snapshot.