Scan returning partial results with 'failOnClusterChange'


#1

Hi, I’m using server Enterprise 3.5.15

I saw this release note in version 3.7.1:

[AER-4645] - (Clustering/Migration) Race condition caused by cluster key changing before disallow_migrations is set.

Could this mean that in my version, a scan would retrieve partial results, even though it used ‘failOnClusterChange’ because of a race condition?

Or this bug fix of 3.0.7.1: [AER-4508] - (Scan) Enhance scan’s migration detection


#2

No, disallow_migrations occurs shortly before a new rebalance, the scan will still detect that migrations have started, when partitions are scheduled.

This was listed as an “improvement” not a “bug”. The functionality was correct before and was the best the server could provide at the time. Before scans had to wait for all namespaces to finish migration. With this change, if a particular namespace has finished migration then scans can operate on this namespace.