anchor.diff:  
   Unfortunately, Kafka is not a key/value store. When a connector starts up, it must scan all messages on the `connect-offsets` topic to find the one it needs. When it updates a previously saved offset, it just appends the new value to this topic without deleting the previous entry. It’s not a problem with connectors that have only a single offset - when updated every minute, this topic would hold roughly 10,000 messages after a week. However, in the case of the Scylla CDC Source Connector this number could be several orders of magnitude larger!
   
  -Fortunately, this issue can be easily mitigated by setting a more aggressive compaction configuration on the `connect-offsets` topic. With the default settings on the Confluent Platform, this topic could grow up to several hundred megabytes after just a few hours (with a Scylla cluster with tens of nodes and very small `offset.flush.interval.ms`). This made the connector startup time slower, as it had to scan the entire offset topic after a start/restart.  By tuning the `segment.bytes`, `segment.ms` or `cleanup.policy`, `retention.ms` we were able to mitigate the problem and significantly reduce the `connect-offsets` topic size. The first two options specify the frequency of the log compaction process. When a segment is compacted, all messages with the same key are reduced to the latest one (the latest offset). Alternatively, setting a shorter retention time (but one that is larger than Scylla’s CDC retention time) proved to be a good option to reduce the offset topic size.
  +Fortunately, this issue can be easily mitigated by setting a more aggressive compaction configuration on the `connect-offsets` topic. With the default configuration of `retention.ms` of 7 days and `segment.bytes` of 1GB, this topic could grow up to several hundred megabytes after just a few hours (with a Scylla cluster with tens of nodes and very small `offset.flush.interval.ms`). This made the connector startup time slower, as it had to scan the entire offset topic after a start/restart.  By tuning the `segment.bytes`, `segment.ms` or `cleanup.policy`, `retention.ms` we were able to mitigate the problem and significantly reduce the `connect-offsets` topic size. The first two options specify the frequency of the log compaction process. When a segment is compacted, all messages with the same key are reduced to the latest one (the latest offset). Alternatively, setting a shorter retention time (but one that is larger than Scylla’s CDC retention time) proved to be a good option to reduce the offset topic size.
   
   === Benchmarks: near linear scaling
   
  
positive.code: 
  However, we quickly realized that by using only the Kafka Connect API, we would have to reimplement a lot of functionality already present in other connectors. We also wanted our connector to be a good citizen in the Kafka community, sticking to the best practices and conventions. That’s exactly why we choose Debezium! 
  
  Thanks to this, when you start the Scylla CDC Source Connector, the configuration parameters will be immediately familiar, as many of them are common with other Debezium connectors. The generated data change events have the same https://javadoc.io/static/io.debezium/debezium-core/0.7.2/io/debezium/data/Envelope.html[Envelope] structure as generated by other Debezium connectors. This similarity allows for the use of many standard Debezium features, such as https://debezium.io/documentation/reference/1.6/transformations/event-flattening.html[New Record State Extraction] [.underline]#.#
  
  == Event representation
  
  
negative.code: 
  The `v2` column is left unchanged after this query and we don’t have any information about its previous value. 
  
  We must be able to represent three possibilities: a column was not modified, a column was assigned a `NULL` value or a column was assigned a non-null value. The representation we chose was inspired by link:/documentation/reference/1.6/connectors/cassandra.html[Debezium Connector for Cassandra], which works by wrapping the value for a column in a structure:
  
  [source,json]
  ----
  