Adding Node in EON is impact on running queries ?

Mujeef

A query is running from last couple of minutes.
While monitoring it take almost resource utilization threshold crosses.
Now I am going to add new node to increase compute power.
After rebalancing shards ,the query is not running on new node.

Can we distribute query on new added node, while a query is running ?

Thanks in advance.

Mujeef

dsprogis

Hi Mujeef,
It is best to add nodes in multiples of shards so that you can have two groups of nodes running a query at the same time. Thus, if you have a three node cluster, adding a fourth of fifth node will not help much until the sixth node is added. This is because a 5-node/3-shard cluster will have one node that is a bottleneck. Once you add the sixth node, the bottleneck is relieved and you will get double the performance of the three-node cluster.
If you are only running one query at a time, adding nodes to the Eon cluster will not improve performance. This is because the number of shards dictates the number of nodes that will participate in a query. Adding nodes to Eon improves concurrency, meaning that more queries can be run at the same time. If you want to improve performance, you can either rebuild your Eon database with more shards or you can switch to Enterprise mode.
I hope this helps.
Dave

Mujeef

Hi Dave,
Thank you very much for your valuable suggestions and guidance.
Just one question :
We are planning for migration from Enterprise to EON.
Is there any way we can achieve this, because we are switching all production to Eon.
How I can copy existing users(Passwords and roles) to eon ?
Can you please advise ?

Thanks,
Mujeef