Veridata is used by Oracle GoldenGate users for checking the data consistency from the source and target. This blog discusses how you would need to check the data consistency in an Active-Active replication.
Let’s say lag is 10 seconds lag time between your databases. You can first run Veridata to find out the what are “potentially” out of sync records. Then you wait for 10 seconds or more seconds (lag + a few seconds, since it may not always be accurate), and then run the report again. This time time comparing only the “potentially” out of sync records. Once that second report run is completed, if there are still out of sync records, you know that those are truly out of sync.
There are still limitations though. If the table keep changing quickly, you then can't use Veridata. For example, an application could have a table that track something like CPU usage. Where each row corresponds to a CPU.. and the rows would be updated very quickly and the same row updated multiple times in a minute.. something like this won’t work well with Veridata, since the rows are going to be constantly changing, it will always look like something is out of sync.
(Thanks Nick Wagner for providing the insight to this.)