THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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- extend the scope of one of the other existing assignment strategies and make it compatible with the DSL of the V1 engine.
- LegacyAssignStrategy
- a primitive O(nodes * replicas) strategy. Basic principle is that nodes are sorted by the number of existing cores, and replicas are assigned in a round-robin fashion in this order. For the number of replicas exceeding the number of nodes this strategy degenerates to equal assignment to nodes without any preference for less loaded nodes or nodes without replicas from the same shard.
- RulesBasedAssignStrategy
- described in detail here: https://lucene.apache.org/solr/guide/8_5/rule-based-replica-placement.html . This is deprecated and was scheduled to be removed, but it implements a significant subset of the V1 policy engine at a comparably minimal execution cost. Many V1 policy rules can be expressed in this legacy rule language (see https://lucene.apache.org/solr/guide/8_5/migrate-to-policy-rule.html). The DSL is different but we could provide a compat shim. Perhaps we should evaluate it as a starting point for V2? This strategy hasn't been tested for performance in very large clusters and very large collections, so It may very well turn out that it has the same inherent performance issues as V1.
- LegacyAssignStrategy