Re: [mongodb-user] A sharded collection is slower than a non sharded one.

[Max Schireson]

For initial loads, you should pre-split. Otherwise initially all records will go into one shard then have to be balanced into others. Pre-splitting will allow the system to distrubute the data among the shards from the beginning.

This shouldn't be an issue in ongoing operations. It is slightly better in 2.2 than earlier but pre-splitting is still recommended for the initial load - the balancing algorithms aren't designed to work with near-empty systems.

-- Max

On Oct 2, 2012 7:57 AM, "Romain P" <fili...@gmail.com> wrote:

Hi,

I work on simple test that insert one million documents in a MongoDB collection.

When the collection is not sharded, the test last 60 seconds.

When the collection is sharded, the test last 140 seconds.

For information purpose : 

The shard key is a random value : doc.__sd.shard = Math.round(Math.random() * 1000)

I have 4 servers splited in 2 replicaset (one primary, one secondary and one arbiter)

The test load balance the data to be inserted on the 4 mongos.

Thank you for your help

Romain

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[Romain]

It worked well !

Thanks

2012/10/2 Romain P <fili...@gmail.com>

Ok I will try it, I'll keep you informed about the performance issue.