Adding new nodes/leafs


#1

I am trying to add more leafs to my cluster. I went back and looked at the manual install setup and registered the hosts, then did the deploy install on each host. Then did the create node, and then add-leaf with the id of the two new nodes. and then ran memsql-admin optimize.

Everything looks good, they are the list of nodes as leafs, two more leafs showed on the Dashboard, and on the Nodes Status page as well. But on the status page I do see only 2 open connections when my other 4 leafs have 25 each.

I went so far as to drop the column store table and setup the pipeline again and all that to import the data fresh to see if that would use all the leafs, but still did not seem to get them mixed in. What else needs to be done to get new leafs


#2

After you add leaves you need to REBALANCE PARTITIONS to spread the data evenly over the leaves. https://docs.memsql.com/sql-reference/v6.7/rebalance-partitions/.

Since parallel query execution is tied to the number of partitions, with a thread per partition, be aware that the speed of one query may not improve if you have too few partitions per node, even if you add more leaves. Adding leaves can give you more throughput for concurrent queries though.

If you need more partitions, you’ll have to create a new database with more partitions and move the data over to it.