SpiderMonkey to V8, mongometer and the Aggregation Framework

I previously posted a comparison that covered running some simple queries against versions 2.2.2 and 2.3.2 of MongoDB. They were pretty basic examples, I just wanted to demonstrate one of the uses of mongometer; comparing the relative performance of MongoDB releases and the MongoDB scripts you write to run on them.

Now I'm going to knock the complexity up a notch and perform a comparison between the different releases of MongoDB, their underlying JavaScript engines using another relatively new feature (added in version 2.1), the Aggregation Framework. I'm going to use the example they have in the documentation, mainly so I don't have to make something up.

{
title : "this is my title" ,
author : "bob" ,
posted : new Date () ,
pageViews : 5 ,
tags : [ "fun" , "good" , "fun" ] ,
comments : [
{ author :"joe" , text : "this is cool" } ,
{ author :"sam" , text : "this is bad" }
],
other : { foo : 5 }
}

db.articles.aggregate(
{ $project : {
author : 1,
tags : 1,
} },
{ $unwind : "$tags" },
{ $group : {
_id : { tags : "$tags" },
authors : { $addToSet : "$author" }
} }
);

I'm populating the collection with data in the form as described above. The only thing I'm adding is that I'm using the JMeter CSV Data Set to populate the author attribute.

Version 2.2.2
So let's make sure we're starting from a clean slate.

$ /usr/lib/mongodb/2.2.2/bin/mongod --port 27000 --dbpath /data/db/2.2.2 --logpath /data/db/2.2.2/mongod.log

$ ps -ef | grep mongo
4974 /usr/lib/mongodb/2.2.2/bin/mongod --port 27000 --dbpath /data/db/2.2.2 --logpath /data/db/2.2.2/mongod.log

$ ./mongo --port 27000

> show dbs
local 0.078125GB
test (empty)



> show dbs
aggregation 0.203125GB
local 0.078125GB
test (empty)

> use aggregation
switched to db aggregation
> db.dropDatabase()
{ "dropped" : "aggregation", "ok" : 1 }

$ sudo kill -15 4974

Version 2.3.2
Let's ensure we have that same clean slate as with Version 2.2.2

$ /usr/lib/mongodb/2.3.2/bin/mongod --port 27001 --dbpath /data/db/2.3.2 --logpath /data/db/2.3.2/mongod.log

$ ps -ef | grep mongo
1463 /usr/lib/mongodb/2.3.2/bin/mongod --port 27001 --dbpath /data/db/2.3.2 --logpath /data/db/2.3.2/mongod.log

$ ./mongo --port 27001

> show dbs
local 0.078125GB
test (empty)



> show dbs
aggregation 0.203125GB
local 0.078125GB
test (empty)

> use aggregation
switched to db aggregation
> db.dropDatabase()
{ "dropped" : "aggregation", "ok" : 1 }

$ sudo kill -15 1463

Conclusions
I ran this a few times and the results were consistent. I'll knock it up another notch over time, and hopefully draw out some useful conclusions, until then, you can draw your own.

Suggestions and comments welcome.