Synapse dedicated SQL pool - 100% Cost in estimated plan for "Compute to Control Node"

Question

Synapse dedicated SQL pool - 100% Cost in estimated plan for "Compute to Control Node"

Paul Hernandez 686 Microsoft Employee

Hi everyone,

I am trying to understand an estimated execution plan for a query running on an sql dedicated pool.

The cost is 100% allocated to the operation "Compute to Control Node".

What does it mean?

We are trying to determine if it worths to create a partition in a small table (only 200K rows) or not. I think compare the two plans could be an option but I cannot understand them and cannot find online documentation.

Could someone please provide some documentation links regarding execution plans on dedicated pools, or is this info currently not available?

BR.
Paul

KranthiPakala-MSFT 46,642 Reputation points Microsoft Employee Moderator

2021-11-03T17:28:15.57+00:00

Hi @Paul Hernandez ,

We still have not heard back from you. Just wanted to check if the below suggestion was helpful? If it answers your query, please do click “Accept Answer” and/or Up-Vote, as it might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

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KranthiPakala-MSFT 46,642 Reputation points Microsoft Employee Moderator

2021-11-03T17:28:15.57+00:00

Hi @Paul Hernandez ,

We still have not heard back from you. Just wanted to check if the below suggestion was helpful? If it answers your query, please do click “Accept Answer” and/or Up-Vote, as it might be beneficial to other community members reading this thread. And, if you have any further query do let us know.

Answer 1

Tom Phillips 17,771

Can you post the XML query plan here https://www.brentozar.com/pastetheplan/.

In answer to your question, partitioning is generally not a query performance enhancement tool. With proper indexing, partitioning will not help query performance.

Partitioning a table that small, will not have any performance impact. Partitioning is really only useful for loading/unloading large amounts of data. For example, billions of rows per month, and you only want to keep a rolling 12 months of data in the table.

Paul Hernandez 686 Reputation points Microsoft Employee

2021-11-08T09:55:56.677+00:00

Hi @Tom Phillips ,

thanks for your reply.

Unfortunately the Bent Ozar tool is not working for me. It gives me the following error:

I attached the two estimated plans in xml format.

Any help will be appreciated.

Best regards,
Paul147293-20211108-my-query-plan-1.xml 147372-20211108-my-query-plan-2.xml

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Synapse dedicated SQL pool - 100% Cost in estimated plan for "Compute to Control Node"

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