Bug report

What Debezium connector do you use and what version?

Mysql Connector - Debezium 2.4.0

What is the issue?

When an incremental snapshot is running, and a lot of input binlog messages are being processed in parallel, the processing performance can become very poor.

After profiling the application, this is correlated to the size of the "dataCollectionsToSnapshot" data structure. In a nutshell, the more tables you snapshot, the worse the performance will get.

Profiling results:

As seen in the results, this is due to the call to "dataCollectionsToSnapshotAsString" for each new binlog records in case a snapshot is running.

This might explain issue DBZ-7256