Added method to build target shard count for subcluster and target load per instance #4359

RiyaTyagi · 2025-06-27T07:16:25Z

What this PR does / why we need it:

After scanning the current load of the cluster we will need to build the target load of the cluster's instances. This includes:

assigning load to each instances based on the nodes in each isolation group. This implementation is similar to that in sharded algorithm with an exception that each instance have the same weight and the number of isolation groups is equal to the replication factor.
assigning the target shard count to subclusters that exists in the placement. If a new subcluster has been added to the placement then we will be moving shards from existing subclusters so that each subcluster has same number of shards.
- If the number of shards in the cluster is not a multiple of the number of subclusters in the placement i.e, numberOfShards % numberOfSubcluster != 0 the extra shards will be assigned to the existing subclusters sorted in ascending order by the subclusterID.
- When a subcluster is removed its shards are moved to existing subcluster and in that case we exclude that subclusterID from the targetShardCount calculation.

RiyaTyagi · 2025-06-27T07:19:46Z

This change is part of the following stack:

_{Change managed by git-spice.}

…ad per instance

RiyaTyagi force-pushed the sub-cluster-3 branch from c819631 to 5a87f46 Compare June 29, 2025 06:40

RiyaTyagi force-pushed the sub-custer-4 branch 2 times, most recently from 05be034 to 890cbfc Compare June 29, 2025 11:16

RiyaTyagi marked this pull request as ready for review June 30, 2025 10:50

Added method to build target shard count for subcluster and target lo…

deea9fe

…ad per instance

RiyaTyagi force-pushed the sub-custer-4 branch from 890cbfc to deea9fe Compare June 30, 2025 11:56

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