question Re: Impala executors and coordinators in Support Questions

Impala executors and coordinators

drgenious — Mon, 08 Nov 2021 08:49:54 GMT

Hi,

What is the difference in impala executors and impala coordinators ? Which one shall I increase in order to run my query faster ?

Thanks in advance

balajip — Mon, 08 Nov 2021 16:25:21 GMT

@drgenious From where you connect with impala-shell that will act as impala coordinator other impala damonens are executors.
If you configured a dedicated coordinator that daemon won't execute any fragments.
For more information about dedicated coordinator please refer to the below doc.
https://docs.cloudera.com/documentation/enterprise/6/6.3/topics/impala_dedicated_coordinator.html

smdas — Thu, 11 Nov 2021 17:14:16 GMT

Thanks for using Cloudera Community. We hope the response by @balajip was helpful for your ask. Additionally, We wish to share a few details:

Your Question points to "How To Make Query Faster". Ideally, Impala would use Parallelism for executing a Query in fragments across Executors. As such, the 1st review should be using Impala Query Profile of the SQL to identify the Time taken at each Phase of SQL Execution. Refer [1] & [2] for few Links around Impala Query Profile.
Once the Phase taking the Most Time is identified, Fine-Tune accordingly. Simply increasing the Impala Executors Daemon or using a Dedicated Coordinator may not be helpful, unless the SQL's Slow Fragment(s) are identified.

Kindly review & let us know if you have any further ask in the Post.

Regards, Smarak