Details
-
Task
-
Resolution: Fixed
-
Major
-
None
-
None
-
KV Sprint 2020-April
Description
New meta-data was added to the 6.5 release, the max-visible seqno. This is a seqno that increments for committed changes (so a prepare or abort will not increment this value). The max-visible seqno is then used to primarily ensure DCP snapshot markers don't include an end-seqno which won't be sent to the client (for clients that don't enable sync-replication).
With the addition of collections we would like to avoid having a per-collection max-visible seqno and it should be possible.
1) The DCP collection's DCP changes will include a new DCP message which collection aware clients will be sent, 'DCP skip' will be sent if a stream's snapshot ends on a prepare/abort.
2) The max-visible seqno as it is today will still exist, but only apply to the default collection. This is because KV still needs to support 'legacy' DCP, those which can only see the default collection.