Hi,
I'd like to better understand which releases are compatible with regard
to user-managed index replication. We ran into issues with replication
in the past, when a leader was erroneously updated before its followers
without stopping replication. The reason seems clear: the follower needs
to understand the Lucene codec that's used by the leader.
It's probably best to always update followers first, or even stop
replication until all instances have been updated.
But is there a way to check, if releases are compatible and leader and
followers could be updated in any order?
I'd think, that I could update the leader first, if leader and follower
releases share the same Lucene version, or if both Lucene versions have
the same value in org.apache.lucene.codecs.Codec.Holder#defaultCodec. Is
that correct, or am I missing something here?
For example, a Solr 9.6.1 follower can still replicate changes from a
Solr 9.7.0 leader, because their Lucene versions (9.10.1 and 9.11.1)
have the same default codec "Lucene99", right? A simple test worked, but
I'm not sure, if that covers all possible cases.
In case it matters: I'm using <codecFactory
class="solr.SchemaCodecFactory"/>.
Thank you!
