 		}, callback
 
 	ensureIndices: () ->
-		# For finding all updates that go into a diff for a doc  (getLastCompressedUpdate, getDocUpdates v > from && v < to)
+		# For finding all updates that go into a diff for a doc
 		db.docHistory.ensureIndex { doc_id: 1, v: 1 }, { background: true }
-		# For finding all updates that affect a project (getProjectUpdates meta.end_ts < before
+		# For finding all updates that affect a project
 		db.docHistory.ensureIndex { project_id: 1, "meta.end_ts": 1 }, { background: true }
 		# For finding all packs that affect a project (use a sparse index so only packs are included)
-		db.docHistory.ensureIndex { project_id: 1, "pack.0.meta.end_ts": 1, "meta.end_ts": 1}	, { background: true, sparse: true }
+		db.docHistory.ensureIndex { project_id: 1, "pack.0.meta.end_ts": 1, "meta.end_ts": 1}, { background: true, sparse: true }
 		# For finding updates that don't yet have a project_id and need it inserting
 		db.docHistory.ensureIndex { doc_id: 1, project_id: 1 }, { background: true }
 		# For finding project meta-data

				return callback null, null if compressedUpdates[0]?.pack? # cannot pop from a pack
				return callback null, compressedUpdates[0] or null

	# only used in this module
	deleteCompressedUpdate: (id, callback = (error) ->) ->
		db.docHistory.remove({ _id: ObjectId(id.toString()) }, callback)

	# used in UpdatesManager
	popLastCompressedUpdate: (doc_id, callback = (error, update) ->) ->
		MongoManager.getLastCompressedUpdate doc_id, (error, update) ->
			return callback(error) if error?

		if options.before?
			query["meta.end_ts"] = { $lt: options.before }

		PackManager.findProjectResults(db.docHistory, query, options.limit, callback)

	backportProjectId: (project_id, doc_id, callback = (error) ->) ->
		db.docHistory.update {
