Write optimized, distributed, scalable indexing store

A mechanism for storing indexing updates is described. A secondary storage system is configured to store a backup of a primary storage system. A plurality of different indexing updates of a data repository associated with the secondary storage system is received. An indexing update may include metadata and/or updates to the metadata for a data item in the backup. The indexing updates may be obtained from an indexing process. At least a portion of the indexing updates are sent for storage in an intermediate store. An indication to commit the indexing updates is received. In response, the indexing updates including the at least the portion of the indexing updates are requested to be committed. The indexing updates batched together into a batch to be committed to a metadata store.