Vertica cluster with unbalanced work load cross nodes

Hi John,

Emoreno's suggestion is a good way to start investigating. Just to modify it, please add "query_type" too in above SQL to see which type of query is not evenly load balances by your application/load_balancer.

In my experience, it is seen that certain type of load creates like "LOAD" events are evenly distributed but 1 application is only firing SELECT DML's to 1 node only which causes this imbalance.

Try using this SQL
select node_name, date_trunc('day',query_start::timestamp) day_query,query_type,count(*) from query_profiles group by 1,2,3 order by 2 desc,1 limit 100;

it has to be some Application issue which is connecting to database.

Regards,
Raghav Agrawal.

thank you very much for your help, those queries do help!

Is your issue solved?? Have a similar issue, but concluded that a projection change is needed.

we were able to find some queries which hits directly to one of our nodes, and redirect them to the load balance, but we are still having the problem of high IO usage., the IO is almost 100% all the time, although CPU and memory are reasonable. Overall queries speed is super slow. Please take a look at the graph below

Can anybody suggest us some ways to determine the reason of problem?
Thank you.

Have you heard of the script vioperf? I wonder if that would help you diagnose what's going on. https://my.vertica.com/docs/8.1.x/HTML/index.htm#Authoring/InstallationGuide/scripts/vioperf.htm?Highlight=vioperf

Thank you, I just tested and here's the result, it looks like the throughput is really low? any way to dive deep into it?

@John_Y I would suggest, profile the queries the db has. Run a designer to get to see what projections you are missing and then Check the tuple mover operations