> db.getSiblingDB('local').oplog.rs.aggregate([
  {$match: {op: 'i', ns: /^test0_fsmdb0.tmp.agg_out/}},
  {$group: {_id: "$ns", count: {$sum: 1}, lastInsertTS: {$max: '$ts'}}},
  {$sort: {count: 1}},
  {$limit: 10},
  {$lookup: {from: 'oplog.rs', localField: '_id', foreignField: 'o.renameCollection', as: 'renameOp'}},
]).pretty()

{
	"_id" : "test0_fsmdb0.tmp.agg_out.688e4b96-01c5-4c1f-a72f-f4f8baef03fa",
	"count" : 4500,
	"lastInsertTS" : Timestamp(1584775195, 41014),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("7b9edb56-0e4b-4f32-ba73-ec7fb66e5c73"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.688e4b96-01c5-4c1f-a72f-f4f8baef03fa",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("0f3a7d7e-6743-4c47-991d-4e4b1ace2b41")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775195, 41515),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:19:55.646Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.3c6eb7b1-89de-4424-a8db-064f7ecac07a",
	"count" : 4500,
	"lastInsertTS" : Timestamp(1584775195, 32008),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("0005df9b-7a39-4be5-8907-0a4717a7fd1a"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.3c6eb7b1-89de-4424-a8db-064f7ecac07a",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("348ceec6-1cde-4dd9-b688-976bf9dca732")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775195, 33009),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:19:55.489Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.7f01dc16-2bdc-4878-8350-3c459ecab7fd",
	"count" : 4500,
	"lastInsertTS" : Timestamp(1584775195, 39012),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("0f3a7d7e-6743-4c47-991d-4e4b1ace2b41"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.7f01dc16-2bdc-4878-8350-3c459ecab7fd",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("c19153fd-80b3-4592-b14e-54916faa6bad")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775195, 39514),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:19:55.626Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.79e1a0d4-72be-4b57-ad8a-bf616ace9d14",
	"count" : 4500,
	"lastInsertTS" : Timestamp(1584775195, 38012),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("c19153fd-80b3-4592-b14e-54916faa6bad"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.79e1a0d4-72be-4b57-ad8a-bf616ace9d14",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("fa29afa9-f98e-4246-862b-3b88860aa4cf")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775195, 39013),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:19:55.618Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.243f2be6-ac90-4fba-99e7-6464435abf44",
	"count" : 4581,
	"lastInsertTS" : Timestamp(1584775195, 33509),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("fa29afa9-f98e-4246-862b-3b88860aa4cf"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.243f2be6-ac90-4fba-99e7-6464435abf44",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("0005df9b-7a39-4be5-8907-0a4717a7fd1a")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775195, 35011),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:19:55.549Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.2717c805-7fbb-4790-b6d2-e4e147e0ff24",
	"count" : 5000,
	"lastInsertTS" : Timestamp(1584775280, 21507),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("35d27aa0-7066-44c5-b255-d75f444dc046"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.2717c805-7fbb-4790-b6d2-e4e147e0ff24",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("d2da711f-6beb-4d89-8563-be5cfd6d3198")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775280, 22508),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:21:20.470Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.a7676b9c-4f4b-4793-8288-e5ef6f0cfa18",
	"count" : 5000,
	"lastInsertTS" : Timestamp(1584775303, 13006),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("43d1b799-f812-414c-8de8-e89441d298ee"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.a7676b9c-4f4b-4793-8288-e5ef6f0cfa18",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("32fa0039-3af0-4300-a309-cb548a77cde2")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775303, 13507),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:21:43.543Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.146078ed-8503-408e-82c9-611feb713bcf",
	"count" : 5000,
	"lastInsertTS" : Timestamp(1584775317, 29011),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("d8b0b391-0c09-49ec-9d46-144fae28a055"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.146078ed-8503-408e-82c9-611feb713bcf",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("1fb39d53-9acd-4442-a1f4-9987c8a3a18f")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775317, 30012),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:21:57.832Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.4abfffcc-c86b-4278-80b6-0051f52224b9",
	"count" : 5000,
	"lastInsertTS" : Timestamp(1584775132, 21500),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("bcb64f87-0ead-44c1-9e45-7e9307efffad"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.4abfffcc-c86b-4278-80b6-0051f52224b9",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("43e7fb16-79d0-40d7-aa70-4e8c089fbfe5")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775132, 26502),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:18:52.245Z"),
			"v" : NumberLong(2)
		}
	]
}
{
	"_id" : "test0_fsmdb0.tmp.agg_out.273135d0-a652-489e-a142-b4399bd102ec",
	"count" : 5000,
	"lastInsertTS" : Timestamp(1584775303, 28009),
	"renameOp" : [
		{
			"op" : "c",
			"ns" : "test0_fsmdb0.$cmd",
			"ui" : UUID("6bb0865b-8719-459b-9282-3c7365821c3d"),
			"o" : {
				"renameCollection" : "test0_fsmdb0.tmp.agg_out.273135d0-a652-489e-a142-b4399bd102ec",
				"to" : "test0_fsmdb0.fsmcoll0_out_agg_match",
				"stayTemp" : false,
				"dropTarget" : UUID("346a1ab4-bd14-4ad2-a3b2-85c7452448c6")
			},
			"o2" : {
				"numRecords" : 5000
			},
			"ts" : Timestamp(1584775303, 28510),
			"t" : NumberLong(1),
			"wall" : ISODate("2020-03-21T07:21:43.704Z"),
			"v" : NumberLong(2)
		}
	]
}