 				delete top.op
 				delete top._id
 				packs.push top
-		# never store the last pack, keep some unpacked ops
-		packs.pop()
-		#
-		if packs.length > docs.length
-			console.log 'not enough compression', packs.length, 'vs', docs.length, 'skipping'
-			return
+			else
+				# keep the op
+				console.log 'keeping large op unchanged'
 
-		console.log 'docs', docs.length, 'packs', packs.length
-		tasks = []
-		for pack, i in packs
-			console.log 'storing pack', i
-			do (pack) ->
-				task = (cb) ->
-					bulk = db.docHistory.initializeOrderedBulkOp();
-					console.log 'insert', pack
-					bulk.insert pack
-					pack.pack.forEach (op) ->
-						console.log 'will remove', op._id
-						bulk.find({_id:op._id}).removeOne()
-					bulk.execute (err, result) ->
-						console.log 'ok?', result.ok, 'nInserted', result.nInserted, 'nRemoved', result.nRemoved
-						cb(err, result)
-				tasks.push task
+		# only store packs with a sufficient number of ops, discard others
+		packs = packs.filter (packObj) ->
+			packObj.pack.length > MIN_COUNT
 
-		async.series tasks, (err, result) ->
-			console.log 'writing packs', err, result.length
+		console.log 'docs', origDocs, 'packs', packs.length
+		async.each packs, insertPack, (err, result) ->
+			if err?
+				console.log 'err', err
+			console.log 'done writing packs'
 			callback err, result
 
-packOpsTask = (doc_id) ->
-	return (callback) ->
-		packOps doc_id, callback
-
-tasks = (packOpsTask id for id in process.argv.slice(2))
-
-async.series tasks, (err, results) ->
-	console.log 'closing db'
-	#console.log util.inspect(results,{depth:null})
-	db.close()
+async.each process.argv.slice(2),	(doc_id, callback) ->
+		packDocHistory(doc_id, callback)
+	, (err, results) ->
+		console.log 'closing db'
+		db.close()

				top.v_end = d.v
				top.meta.end_ts = d.meta.end_ts
				return
			else
				# create a new pack
				top = _.clone(d)
				top.pack = [ {v: d.v, meta: d.meta,  op: d.op, _id: d._id} ]

_ = require 'underscore'
MAX_SIZE = 1024*1024
MAX_COUNT = 1024
MIN_COUNT = 100
KEEP_OPS = 100

insertPack = (packObj, callback) ->
	bulk = db.docHistory.initializeOrderedBulkOp();
	expect_nInserted = 1
	expect_nRemoved = packObj.pack.length
	console.log 'inserting', expect_nInserted, 'pack, will remove', expect_nRemoved, 'ops'
	bulk.insert packObj
	packObj.pack.forEach (op) ->
		bulk.find({_id:op._id}).removeOne()
	bulk.execute (err, result) ->
		if err? or result.nInserted != expect_nInserted or result.nRemoved != expect_nRemoved
			console.log err, result
			console.log 'nInserted', result.nInserted, 'nRemoved', result.nRemoved
		callback(err, result)

packDocHistory = (doc_id, callback) ->
	console.log 'packing doc_id', doc_id
	db.docHistory.find({doc_id:mongojs.ObjectId(doc_id),pack:{$exists:false}}).sort {v:1}, (err, docs) ->
		packs = []
		top = null
		origDocs = docs.length
		# keep the last KEEP_OPS as individual ops
		docs = docs.slice(0,-KEEP_OPS)
		docs.forEach (d,i) ->
			sz = BSON.calculateObjectSize(d)
			if top?	&& top.pack.length < MAX_COUNT && top.sz + sz < MAX_SIZE
