Sharded repodata

conda-libmamba-solver supports CEP-16 Sharded Repodata.

Sharded repodata splits repodata.json into an index mapping package names to shard hashes in repodata_shards.msgpack.zst. A shard contains repodata for every package with a given name. Sharded repodata makes it possible to quickly build a subset of repodata including all requested packages and their transitive dependencies, which is much smaller than the repodata for all packages in the channel.

As of conda-libmamba-solver 26.6, conda-libmamba-solver delegates to conda for its sharded repodata implementation. LibMambaIndexHelper accepts an optional build_repodata_subset function that it uses to fetch sharded repodata. See conda’s build_repodata_subset API and BuildRepodataSubset protocol for more information.