CouchDB uses sequential UUID by default: https://docs.couchdb.org/en/stable/config/misc.html#uuids-configuration https://docs.couchdb.org/en/stable/config/misc.

CouchDB uses sequential UUID by default: https://docs.couchdb.org/en/stable/config/misc.html#uuids-configuration https://docs.couchdb.org/en/stable/config/misc.html#uuids-co... > Impact of UUID choices: the choice of UUID has a significant impact on the layout of the B-tree, prior to compaction. > For example, using a sequential UUID algorithm while uploading a large batch of documents will avoid the need to rewrite many intermediate B-tree nodes. A random UUID algorithm may require rewriting intermediate nodes on a regular basis, resulting in significantly decreased throughput and wasted disk space space due to the append-only B-tree design. > It is generally recommended to set your own UUIDs, or use the sequential algorithm unless you have a specific need and take into account the likely need for compaction to re-balance the B-tree and reclaim wasted space.