Change Data Capture Extract: When you set up GG for DAA to keep the source data synchronized with another set of data, the Extract process captures the DML and (if supported) DDL operations performed on the configured objects after the initial synchronization has taken place. It stores these operations until it receives commit records or rollbacks for the transactions that contain them. If it receives a rollback, it discards the operations for that transaction. If it receives a commit, it persists the transaction to disk in a series of files called a trail, where it is queued for propagation to the target system. All the operations in each transaction are written to the trail and are in the order in which they were committed to the source technology. This design ensures both speed and data integrity. The format of the data written to trail files depends on the source technology.