A mechanism for querying a label-aware index in the context of versioning is provided. The key of the label-aware index is a composite key and includes a unique label identifier, corresponding to a specific label, and the key of the original index, which key itself may be a composite key. The label-aware index may be implemented as an index-organized table. The label-aware index is organized on disk first by the label identifier and then by the original index key so that queries of versions of resources within a particular label are as efficient as queries on an index of an unversioned repository with the same number of resources.